Compendium of Student Papers: 2014 Undergraduate Transportation Scholars Program

David Florence, Sam Jordan, Nicole L. Kelly and Kaitlynn Dione Simmons, Authors, and H. Gene Hawkins, Editor, August 2014

This report is a compendium of research papers written by students participating in the 2014 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 24th year, provides undergraduate students in civil engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas A&M Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics: 1) Using Psychology to Understand Managed Lane Use; 2) Performance Characterization of Different Asphalt Binders at High Temperature: Oklahoma Case Studies; 3) Rapid Rehabilitation of Energy Impacted Roads; and 4) Benefit-Cost Analysis of Horizontal Curve Traffic Control Treatments.

Keywords: Managed Lane; Asphalt Binders; Energy Impacted Roads; Horizontal Curve, Traffic Control, Treatments

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Compendium of Student Papers: 2016 Undergraduate Transportation Scholars Program

Mitchell P. Fisher, II and Christopher Garcia, Authors, and H. Gene Hawkins, Editor, August 2016

This report is a compendium of research papers written by students participating in the 2016 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 26^th year, provides undergraduate students in civil engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas A&M Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics: 1) Generalized Trends in Wrong-Way Driving; and 2) Travel Rates of an Aging Population: A Texas Analysis.

Keywords: Wrong-Way Driving, Travel Rates, Aging Population

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Modeling Deformation of Freezing Concrete: Towards the Identification of D-cracking Susceptible Aggregates and Construction of all Concrete LNG Tanks

Syeda Farhana Rahman, December, 2016

For many decades, degradation of concrete by freezing actions has been a primary interest of research for civil engineers. Past studies mostly relied on expensive and time-consuming experimental or semi-empirical investigations to identify the source of damage that is attributable to substandard aggregates, inadequate entrained air content, highly porous mortar or cement matrix, and use of deicing salts. Theoretical works developed in recent years do not incorporate all these factors in one single model. Very recently, concrete has gained widespread popularity as a cheap alternative to traditional material utilized for containing liquefied natural gas (LNG). Most studies documenting concrete behavior at cryogenic temperatures are obscure. Therefore, poroelastic theory, capable of incorporating aggregate and mortar properties, pore solution characteristics, air void spacing, and environmental exposure has been utilized to model damage triggering stresses and strain in concrete used for two purposes: 1) concrete pavement exposed to freezing and thawing cycles, and 2) concrete walled tanks containing LNG. The solid-liquid phase transformation equilibrium has been redeveloped to demonstrate the effect of pore solution speciation and disjoining pressure on the deformation of freezing concrete.

The modeled trends are in good agreement with experimental results obtained from literature. It has been found that the damage initiating tensile stresses, exhibited at the aggregate-matrix boundary for both the air-entrained and non-air-entrained concrete, can be exacerbated by the Mandel-Cryer effect induced by the delayed relaxation of the pore pressure from the aggregate center. The model suggests that high-porosity, low-permeability aggregates are the most vulnerable to D-cracking. Concrete with low-porosity, low-permeability mortar matrix, typical of mortar containing supplementary cementitious materials and/or low water to cement ratio, can withstand freezing deformation even with a spacing factor larger than the recommended value. In addition, thermodynamic analysis shows that the disjoining force favors crystal growth, while the dissolved ions suppress the freezing point but are still capable of building high hydraulic pressure in the pore network. We believe that implementation of these models will help practitioners select appropriate combinations and proportions of concrete mixture constituents to build safe, economic, and durable concrete structures.

Keywords: Concrete, Deformation, LNG Tanks, Freeze Thaw Cycle

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Integration of Heuristics and Statistics to Improve the Quality of Network-level Pavement Condition Data

Salar Zabihi Siabil, December, 2016

Transportation agencies use pavement management systems (PMSs) to make efficient decisions about allocating available resources to the maintenance, rehabilitation, and renewal of their roadway networks. One of the most costly parts of the PMS process is collecting pavement condition data. The efficiency and reliability of decisions made based on PMSs depend upon the quality of this data. Thus, transportation agencies need to ensure that dollars invested in this data are well spent, and pavement condition data has the level of quality necessary to meet PMS requirements. Therefore, assessing and improving the quality of pavement management data is a major challenge for both researchers and practitioners.

This study advances the quality assessment of network-level pavement condition data by answering the following questions: (a) How can we identify potential errors in pavement condition data used in PMSs? (b) How do multiple dimensions of error detection affect our ability to detect errors? (c) How does the accuracy of pavement condition data impact predictions of future road network performance? And (d) How do we measure multiple quality dimensions of pavement condition datasets? First, this research devises and implements a computational method to identify potential errors in pavement condition data, integrating conventional statistical methods and heuristics. Second, the effect of considering multiple dimensions of error detection in pavement condition data was investigated. These dimensions are based on data properties, including time series trends in pavement condition data, variability within uniform performance families, and the consistency between several performance indicators. Third, this research presents a quantitative assessment of the impact of data accuracy on the estimated remaining service life (RSL) of a roadway network as an overall measure of network health. Finally, it provides metrics for measuring data quality dimensions for pavement condition datasets.

The developed technique was validated using pavement condition field data for a road network in Texas. The technique has the advantage of differentiating between extreme yet valid data points and potential errors. In addition, accounting for several properties of pavement condition data to identify potential errors improves the results of this technique. It is hoped that this research will enable pavement engineers to identify potential errors in pavement condition data, and more effectively assure data quality.

Keywords: Pavement Management Systems, Pavement Condition, Road Network, Performance

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Waterway System Maintenance Optimization

Mahammadadel Khodakrami, August, 2016

Coastal lines, harbors/ports, and inland waterways constitute the marine transportation system, a major component of the United States freight system, carrying a vast majority of foreign imports and exports and a significant amount of domestic freight. This system needs regular maintenance. US Army Corps of Engineers (USACE) is in charge of the waterway system maintenance. However, the limited maintenance budget needs to accommodate a large number of maintenance requests for dredging and dam repair, etc. The requests often exceed the budget available by much. A decision facing the USACE management is what projects to fund and how to select them. This research aims at providing the necessary models and tools to facilitate maintenance decisions at the USACE. The objective is to maximize the overall system improvement under annual limited budget. The underlying problem can be modeled as a knapsack problem with an additional constraint that increases the problem complexity. The additional constraints describe the benefit interdependency of different maintenance projects due to the waterways network effect.

This research tackles the maintenance problem at different levels. First, an integer selection model is developed to find the optimal set of dredging projects (waterway sediment removal operation) and some heuristics are developed to provide near-optimal solutions in computationally guaranteed polynomial time. Next, a model is developed to allow partial dredging. Partial dredging means partially conducting the requested dredging operation. The model is able to determine the percentage of the dredging depth to fund instead of a zero-one dredging decision for each project.

Further, a stochastic problem is considered regarding to the probabilistic shoaling process. To solve the probabilistic problem, two methods are designed: an analytical model that takes account of probability in terms of expected values, and a stochastic optimization approach was developed based on Monte-Carlo simulation.

Finally, the problem is modeled in a multi-modal context where the maintenance decisions are made simultaneously on dredging and lock/dam improvement. In this multimodal model, the effect of landside modes’ capacity is considered comprehensively. All the developed methods are tested with real examples from US marine network and their performance is approved by comparison to real situation.

Keywords: Waterway, Maintenance, Dredging

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The Contribution of Micro- and Macro-texture to the Skid Resistance of Flexible Pavement

Pedro A. Serigos, Prasad Buddhavarapu, Grant M. Gorman, Feng Hong, and Jorge A. Prozzi, February 2016

Skid resistance is an important characteristic of the pavement surface to reduce the number of road accidents. The mechanisms involved in the activation of the frictional force required for a safe braking of the vehicle depend on both the macro- and the micro-texture of the pavement surface. The state-of-the-practice methodologies commonly used for measuring pavement texture at highway speeds only account for the macro-texture, which alone might not be sufficient to effectively characterize skid resistance. This study explored different ways to characterize the micro-texture of pavement surfaces with the main objective of quantifying the effect of accounting for both the micro and the macro components of the texture, rather than just the macro-texture, on the prediction of skid resistance.

The friction and texture data analyzed in this study were collected from an experiment conducted on in-service flexible pavement surfaces. Surface friction was measured using a British Pendulum Tester whereas texture data was collected using a Circular Track Meter and a Laser Texture Scanner. The surface micro-texture was characterized by different texture parameters calculated in both the spectral and the spatial domain. The impact of incorporating the micro-texture on the prediction of skid resistance was evaluated by analyzing a series of models specified by each of the proposed parameters. The results of the analyses show a significant improvement in predicting the surface friction when accounting for both components of the surface texture, as opposed to only the macro-texture. Furthermore, the parameters calculated on the frequency domain led to a better prediction power.

Keywords: Micro-texture, Macro-texture, Skid Resistance, Laser Texture Scanner, Spectral Analysis

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A Synthesis Report of Purpose and Need: Assessment of Event Egress for Houston’s Reliant Stadium

Carol Abel Lewis, Ph.D., Latissha Clark, Velyjha Southern, December 2015

Attendance at large arena events is increasing, as the seats are added, and ground level activities such as tailgating attract visitors not attending the game. Access is somewhat staggered as people choose their arrival times differently. However, the egress is far more concentrated with visitors largely attempting to leave simultaneously. The prevailing approach is to place police officers, who communicate via radio, at proximate exit locations. Further complicating the egress are those who arrive by public transportation and are transported by scheduled train cycles or queued buses. Once filled, users wait for the next cycle. Given advances in technology from the perspective of handheld devices and traffic management software, it is timely to reexamine protocol and strategies to determine whether an opportunity exists to facilitate or streamline egress, specifically looking at NRG Stadium in Houston. This work convened stakeholders familiar with NRG stadium in Houston, Texas to detail concepts to potentially improve egress, particularly in consideration of Super Bowl XLIX to be held at NRG in 2017.

Keywords: Projecting Demand, Intercity Passenger Volumes

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The Opportunities and Tensions of Historic Preservation and Transit Oriented Development

John Renne, David Listokin, Tara Tolford, Kim Mosby and James Amdal, December 2015

In recent years, there has been much research on Transit Oriented Development (TOD) in the United States and abroad. There has been decades of study of historic preservation, both in the United States and internationally. Yet the intersection of TOD and historic preservation has received scant attention. This project cross-references data on TOD and historic preservation, examines case studies of where TOD and historic preservation intersect and recommends policy and tools for preservation in TODs.

Keywords: Preservation, Transit Oriented Development

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Boundary Conditions Estimation on a Road Network Using Compressed Sensing

Michele Simoni, Ofer Eldad, Andrew Alexander and Christian Claudel, February 2016

This report presents a new boundary condition estimation framework for transportation networks in which the state is modeled by a first order scalar conservation law. Using an equivalent formulation based on Hamilton-Jacobi equation, we pose the problem of estimating the boundary conditions of the system on a network, as a Mixed Integer Linear Program (MILP). We show that this framework can handle various types of traffic flow measurements, including floating car data or flow measurements. To regularize the solutions, we propose a compressed sensing approach in which the objective is to minimize the variations over time (in the L1 norm sense) of the boundary flows of the network. We show that this additional requirement can be integrated in the original MILP formulation, and can be solved efficiently for small to medium scale problems.

Keywords: OD Matrix Estimation, Flow Model, Mixed Integer Linear Programming

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Assessment of Vehicle Performance in Harsh Environments Using LSU Driving Simulator and Numerical Simulations

Steve C. S. Cai, Sherif Ishak, and Jiexuan Hu, December 2015

With the economic booming development of coastal areas, the importance of the traffic planning becomes obvious not only in a hurricane evacuation but also in the daily transportation. Vehicle performance on the freeway during harsh environments is critical to the success of the planning process. The present study aims to study the effect of harsh environments on the driving behavior and vehicle performance. The driving simulator installed in Louisiana State University was used to investigate the driver’s behavior and vehicle performance in different adverse conditions such as strong crosswinds, wet road surface, and curving. Modified parameters of the driving simulator were determined to reproduce the real wind loadings according to the vehicle velocity and wind velocity, through the manipulation of appropriate software. While the vehicle performance was recorded in terms of lane offset, vehicle velocity, and heading error, the driver’s reaction was measured in the form of the reaction time, steering angle, and the time of pressing on brake and gas pedal, respectively. The results illustrate that a higher wind speed leads to more variance of lane offset and heading error. The rainy weather/wet road surface does have an effect on the vehicle velocity in a strong wind environment. The findings of this study demonstrate the valuable use of a driving simulator to represent different hazardous driving conditions and to develop a statistic model to predict and estimate the driver’s behavior and vehicle performance.

Keywords: Wind Forces, CFD, Vehicle Performance, Driving Behavior, Driving Simulator

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A Decision Support Tool for Selecting Traffic Control Devices

James Robertson and H. Gene Hawkins, Jr., July 2015

The Federal Highway Administration (FHWA) and transportation profession continue updating and publishing the Manual on Uniform Traffic Control Devices (MUTCD). However, it is beyond the scope of the MUTCD to provide the breadth of knowledge necessary for evaluating traffic control devices (TCDs) as part of the larger transportation system. In this report, researchers use existing theory and a survey of transportation professionals to develop a decision support tool for use in selecting TCDs. To accomplish this, researchers first use a survey of transportation professionals to evaluate the relative importance of safety, mobility, environmental sustainability, and economic activity when selecting TCDs. This investigation leads researchers to conclude that the best solution meets local needs and desires, conforms to engineering principles and practice, and provides an engineering benefit. Additionally, this investigation finds that safety and mobility are the engineering benefits driving the selection of TCDs. Next, researchers use a portion of the same survey of transportation professionals to evaluate the importance of crashes, driver compliance, and mobility when ranking transportation alternatives. This investigation finds that compliance is a reasonable surrogate measure of safety in the absence of crash data. Additionally, within this evaluation, researchers identify performance measures for use in selecting traffic control devices. Finally, researchers use the relative importance of agency objectives evaluation and the identified performance measures to develop a decision support tool for use in selecting TCDs. Researchers demonstrate the use of this decision support tool with a case study.

Keywords: Traffic Control Devices, Decision Theory, Performance Management, Performance Measurement

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Queue Length Estimation and Platoon Recognition using Connected Vehicle Technology for Adaptive Signal Control

Kamonthep Tiaprasert, December, 2015

This dissertation presents mathematical and analytical models for real-time queue length estimation and platoon recognition using the connected vehicle technology (CVT). Information on queue length and platoon is a crucial part of traffic signal control and is difficult to obtain accurately with traditional technologies such as loop detectors. The past studies are either limited to fixed-time signal control or lacked verification on the applicable range or evaluation of the performance of algorithms.

The proposed algorithms focused on estimating the queue length for adaptive signal control and platoon characteristics for signal coordination and adaptive signal control. For queue length detection, an algorithm was developed to determine the estimated value between the last stopped vehicle and the first moving vehicle for different market penetration ratios. Discrete wavelet transform is applied to the estimated queue lengths to improve accuracy and consistency.

The platoon recognition model is developed based on time headway so that the arrival times can be computed directly from the estimated platoon data. First, the detected platoon is identified by a modified critical time-headway. Then, platoon size and starting and ending times are estimated. Lastly, a filtering process for “qualified” detection platoon is proposed to optimize detectability. The results show that the proposed algorithms can estimate well in various traffic conditions and under both fixed-time and actuated signal control without relying on inputs that are hard to obtain in practice. Furthermore, an analytical model to estimate the platoon detection rate is proposed and shown to be close to the numerical results. Therefore, traffic engineers can use the analytical model to estimate the required market penetration ratio for the application without field experiments or microscopic simulation. Accordingly, the proposed algorithms can be an important part of adaptive signal control focusing on real-time coordination.

Keywords: Connected Vehicle, Connected Vehicle Technology, Adaptive Signal Control

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Optimization and Mechanism Design for Ridesharing Services

Wei Lu, December, 2014

This research studies operations research problems of ridesharing services. In the first part of the research, the large-scale ridesharing optimization problem (RSP) is formally defined with its complexity analyzed. A mixed-integer program is then developed to solve RSP to optimality. Since RSP is NP-hard, heuristic algorithms are developed to efficiently solve larger instances of RSP. The quality of heuristic solutions is evaluated by comparing with benchmark algorithms. Experimental results showed that the solutions produced by heuristic are good-enough approximation of the optimum and outperformed the matching solution by a non-trivial margin. The second part of this dissertation studies the fairness and stability problems in ridesharing. The fair cost allocation problem in ridesharing is formulated as a cooperative game. An algorithm based on coalition generation techniques is developed to efficiently find the nucleolus of this game. Experiments showed that this algorithm could save significant amount of computational resources compared to the enumeration method. The output of this research provides both insights and tools for understanding and operating large-scale ridesharing services.

Keywords: Ridesharing, Optimization, Heuristic, Mixed-integer Programming, Game Theory, Mechanism Design, Nucleolus

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Link Travel Time Estimation Based on Network Entry/Exit Time Stamps of Trips

Wen Wang, December 2015

This dissertation studies the travel time estimation at roadway link level using entry/exit time stamps of trips on a steady-state transportation network. We propose two inference methods based on the likelihood principle, assuming each link associates with a random travel time. The first method considers independent and Gaussian distributed link travel times, using the additive property that trip time has a closed-form distribution as the summation of link travel times. We particularly analyze the mean estimates when the variances of trip time estimates are known with a high degree of precision and examine the uniqueness of solutions. Two cases are discussed in detail: one with known paths of all trips and the other with unknown paths of some trips. We apply the Gaussian mixture model and the Expectation- Maximization (EM) algorithm to deal with the latter. The second method splits trip time proportionally among links traversed to deal with more general link travel time distributions such as log-normal. This approach builds upon an expected log-likelihood function which naturally leads to an iterative procedure analogous to the EM algorithm for solutions. Simulation tests on a simple nine-link network and on the Sioux Falls network respectively indicate that the two methods both perform well. The second method (i.e., trip splitting approximation) generally runs faster but with larger errors of estimated standard deviations of link travel times.

Keywords: Travel Time Estimation, Gaussian Distribution, Traffic, Mobility, Network Efficiency

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Real Option Analysis to Value Managed Lanes

Sunghoon Lee, May 2016

Managed lanes (MLs) provide a backup option for travelers even when they do not use MLs. For example, travelers have the option to use MLs when they encounter unexpected congestion. The option value of MLs refers to travelers’ willingness to pay for having the ML option for possible use in the future. Despite the potential benefit of MLs, earlier studies have only considered the actual use benefits of MLs, such as travel time savings.

This research used detailed travel data from both MLs and general purpose lanes (GPLs) of the Katy Freeway (I-10) in Houston. From these data, revealed preferences between MLs and GPLs of all travelers with a transponder in 2012 were identified. This research examined two potential definitions of travelers who valued MLs as a travel option. These definitions included 1) travelers who used MLs at least once in 2012 and 2) all travelers with transponders (even those who never used MLs). This research found that the travelers who never used the MLs in 2012 were extremely unlikely to use the MLs in all of 2013. Thus, this research recommends ML option users to be defined as only those travelers who used MLs at least once in 2012.

This research used the Small-Rosen log sum method (1981) and the Black-Scholes option pricing method (1973) to estimate the option value of MLs. The log sum method estimates the option value by measuring change in consumer surplus between the situation where both MLs and GPLs are available and the situation where only GPLs are available. The Black-Scholes method was originally developed to price options in stock markets and was modified to estimate the option value of MLs in this research. This research found that the log sum method frequently provided a poor estimate of the option value. Thus, this research recommends the Black-Scholes method to estimate the option value of MLs. The option value of the MLs was found to be similar to the value of travel time savings from the MLs for the ML option users. Thus, the option value of MLs is an important component of the total value of MLs.

Keywords: Managed Lanes, General Purpose Lanes, Option Value, Value of Travel Time

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The Gulf Coast Megaregion: In Search of a New Scale to Understand Freight Transportation and Economic Development

Bethany Stich, Kyle Griffith and Peter Webb, October 2015

Jane Jacobs famously wrote, “The economic foundation of cities is trade.” Increased global connectivity and expanding domestic markets around major city hubs have led to a spatial reorganization of regional economies towards a higher level of scale referred to as the megaregion. These trade networks rely on a complex mix of freight and telecommunications infrastructure, low trade barriers, as well as international business and social networks. Policymakers have a responsibility to recognize the vital relationship between economies and freight, and it is imperative that national policies reflect the domestic and global environments in which megaregions must now compete. The United States (US) lacks a national freight strategy and most metropolitan areas fail to implement comprehensive trade strategies, indicating disconnect between policy and practice. In this research, we determine the status of freight planning strategies at the megaregion scale of an economically integrated section of the United States Gulf Coast.

Keywords: Freight Planning, Megaregion, Trade, Economic Development

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Developing a Methodology for Projecting Intercity Commuting

Carol Abel Lewis, Vincent Hassell, Veronica Green, December 2015

Texas agencies are investigating passenger rail options in several corridors connecting people between the state’s major cities. Popular thinking is that there is commuter travel between a number of these markets. In specific, Austin to Houston and Dallas to Houston rank as highly desirable connections to be made by passenger rail. There has been significant study of corridors linking Austin, Dallas and San Antonio; but little research considers the State Highway 290 corridor that would link Houston to Austin. A tool to project the commuter travel between these cities would be beneficial for Metropolitan Planning Organizations (MPOs) and local transit authorities. This research seeks to assess existing methodologies, and then modify, develop and recommend for testing a methodology to determine the volume and frequency of commuter travel between these markets.

Keywords: Projecting Demand, Intercity Passenger Volumes

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Manual Traffic Control for Planned Special Events and Emergencies

Scott Parr and Brian Wolshon, November 2015

Manual traffic control is a common intersection control strategy in which trained personnel, typically police law enforcement officers, allocate intersection right-of-way to approaching vehicles. Manual intersection control is a key part of managing traffic during emergencies and planned special events. Despite the long history of manual traffic control throughout the world and its assumed effectiveness, there have been no quantitative, systematic studies of when, where, and how it should be used or compared to traditional traffic control devices.

The goal of this research was to quantify the effect of manual traffic control on intersection operations and to develop a quantitative model to describe the decision-making of police officers directing traffic for special events and emergencies. This was accomplished by collecting video data of police officers directing traffic at several special events in Baton Rouge, LA and Miami Gardens, FL. These data were used to develop a discrete choice model (logit model) capable of estimating police officer’s choice probabilities on a second-by-second basis. This model was able to be programmed into a microscopic traffic simulation software system to serve as the signal controller for the study intersections, effectively simulating the primary control decision activities of the police officer directing traffic. The research findings suggested police officers irrespective of their location, tended to direct traffic in a similar fashion; extending green time for high demand directions while avoiding gaps in the traffic stream.

Keywords: Manual Traffic Control, Emergency Evacuation, Microsimulation, Logit Model

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Assessing the Potential for Gulf Coast NAFTA Maritime Trade Corridors

Bethany Stich, Kyle Griffith, Peter Webb, Brittany Waggener and James Amdal, December 2015

The North American Free Trade Agreement (NAFTA) was enacted in 1994 with the expressed intent of reducing barriers to trade. Since that time, however, transborder congestion and delays between the United States (US) and Mexico threaten achievement of this goal. As a partial mitigation strategy, maritime shipping offers a modal alternative for NAFTA trade with the potential for not only strengthening the resiliency of the North American transportation system, but also alleviating congestion for traditional overland modes. To that end, Gulf Coast economies are preparing for increased shipping activity in both vessel size and commodity volumes upon completion of the Panama Canal expansion by 2016. This study assesses the potential for maritime shipping corridors in the Gulf of Mexico between the US, Mexico, and Cuba. We document current trade patterns and infrastructure, analyze potential opportunities for trade expansion, and analyze the policy barriers that need to be addressed to strengthen these maritime trade corridors. The prospect of reduced transborder congestion, increased system resilience, and expanded economic cooperation with Cuba has opened a policy window for more deliberate coordination between national and state governments to make the necessary infrastructure investments and policy changes to bolster maritime shipping capacity.

Keywords: Freight Flows, NAFTA, Cuba, Modal Shift, International Trade

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Proposing Transportation Designs and Concepts to Make Houston METRO’s Southeast Line at the Palm Center Area more Walkable, Bikeable, and Livable

Khosro Godazi, Latissha Clark, and Vincent Hassell, December 2015

Over the years, the Palm Center (PC) in Houston, Texas, has been the beneficiary of several economic development endeavors designed to ignite economic and community growth and revitalization. While these endeavors brought forth initial success, they have failed to transform the PC into a lasting model of economic growth and prosperity and to inspire community pride and engagement. The development of METRO’s Southeast Line light rail station at the Palm Center Transit Center presents the prime opportunity for meeting the needs of the community by implementing design concepts and principles that provide social, environmental, and economic benefits to those living within close proximity of the transit station.

The objective of this study is to explore community partnerships and initiatives, Transit Oriented Development (TOD) and livable center concepts and principles, features from previously successful TODs, and lessons learned from past development initiatives designed to foster revitalization. The information gathered will be synthesized and presented as recommendations to help ensure the PC area reaches its full social, environmental and economic potential. The outcome of this project will provide communities, local government and transportation planning agencies with innovative ideas and planning strategies that will place the PC area on the path to sustainable growth and prosperity.

Keywords: Transit Oriented Development, TOD, Redevelopment around Transit, Revitalization

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The Conceptual Mismatch: Transportation Stressors and Experiences for Low-Income Adults

Kate Lowe, Kim Mosby, and Tara Tolford, October 2015

Physical access to jobs has long been identified as a barrier to employment and earnings, with prior research identifying the “spatial mismatch” between suburban entry-level jobs and low-income workers. However, existing transportation research on physical access fails to adequately account for the complex role that transportation needs, stressors, benefits, and costs play in low-income households. Through qualitative analysis, this study examines the role of transportation in the lives of low-income adults in two medium-sized metropolitan areas and how their actual, lived transportation experiences function as stressors with potentially compounding impacts. The study finds that job accessibility models that only account for travel time and location may not reflect the transportation time tax associated with accessing employment for some low-income households.

Keywords: Transit, Spatial Mismatch, Job Access, Well-being

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Achieving Regional Fare Integration in New Orleans: Innovative Cost Sharing Arrangements and Technologies

Vivek Shah (UNO Transportation Institute), Rachel Heiligman (Ride New Orleans), Alexandra Miller (Ride New Orleans), September 2015

Many regions across the country have more than one transit agency providing vital public transportation services. While a transit agency may see their role limited by a jurisdictional boundary, transit riders’ commutes know no such political boundaries. For those riders whose commutes are reliant on one or more transit agencies, a fractured fare system among the various transit agencies they ride means higher user costs. This study will examine the history of regional fare integration in the New Orleans metropolitan region, and the challenges and successes of varying approaches taken by transit agencies in various metropolitan regions, to reveal options for achieving regional fare integration in New Orleans today.

Keywords: Transit, Regionalism, Fare Technology, Cost Sharing

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Evaluation of Complete Streets Policy Implementation by Metropolitan Planning Organizations

Tara Tolford, Billy Fields, and Tom Longoria, September 2015

Over the last ten years, communities around the country have begun to implement comprehensive reforms designed to ensure that roadway users of all ages and abilities can safely utilize the transportation system. This complete streets policy framework has emerged as an important tool for communities to improve opportunities for active living with over 500 policies adopted nationwide.

Complete streets policy diffusion has been rapid, but uneven, and the extent to which policy adoption is making a difference in the implementation of projects at the local and regional level is unclear. This research project seeks to address this need through a national survey of the 385 metropolitan planning organizations (MPOs) around the country, evaluating the extent to which complete streets policies are being adopted and implemented at the MPO level, what opportunities and barriers to complete streets exist, and implications for future policy diffusion and innovation efforts.

Keywords: Complete Streets, Metropolitan Planning Organizations, MAP-21, Non-motorized Transportation

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Spread Prestressed Concrete Slab Beam Bridges

Mary Beth D. Hueste, John B. Mander, Tevfik Terzioglu, Dongqi Jiang, and Joel Petersen-Gauthier, April 2015

TxDOT uses prestressed slab beam bridges for short-span bridges ranging from approximately 30–50 ft in length. These bridges have precast, pretensioned slab beams placed immediately adjacent to one another with a cast-in-place slab made composite with the beams. While these bridges are used extensively, they are more expensive than traditional prestressed I-beam structures on a per-square-foot basis. The objective of this project was to investigate the use of slab beams that are spread apart with precast panel stay-in-place forms between beams and a cast-in-place concrete deck, and to develop appropriate design guidelines for this alternate spread slab beam bridge system.

The project objectives were met through a series of tasks. The research team reviewed the relevant literature and the current state of the practice. Preliminary designs were developed to assess the potential of a spread slab beam bridge system. A full-scale spread slab beam bridge was constructed at the Texas A&M University Riverside Campus and tested to assess constructability, in-service performance, and behavior. Field testing was conducted for the Riverside Bridge and a US 69 on-system bridge to evaluate load distribution behavior and to provide data to guide analytical modeling of this bridge system. Additional analytical models were developed to investigate an array of possible bridge geometries and load sharing behavior. Based on these models, recommendations were developed for load distribution factor relationships for the design of spread slab beam bridges.

Keywords: Precast Prestressed Concrete, Bridge Girders, Spread Slab Beams, Load Distribution Factors

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Forecasting the Impacts of Shale Gas Developments on Public Health and Transportation Systems on Both Sides of the Mexico-U.S. Border

Zenon Medina-Cetina, Patricia Varela, August 2015

The activities completed for this project includes the literature research on the Eagle Ford formation, the review of public-health and transportation related variables to shale gas developments, and the definition of the project collaborative site at Prof. Medina-Cetina’s Stochastic Geomechanics Laboratory SGL server.

Also, a collection of spatial data from the Eagle Ford Shale, including transportation infrastructure, geology, hydrology, demography, and well production was gathered. In this project, researchers developed an improvement of the proposed Bayesian Network for the regional assessment of environmental and social risk (i.e., transportation infrastructure and public health) by enhancing the BN+GIS Model for Environmental Sensibility assessment including a Surface Water variable. This required the improvement and optimization of the code producing BN+GIS results to reduce computational time. Afterward, researchers attained results on the implementation of enhanced BN+GIS model in the Barnett Shale Play. Consequently, researchers completed a paper to be submitted in the ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems named “Bayesian Networks and Geographical Information Systems for Environmental Risk Assessment for Oil and gas Site Developments.”

Following up this activity, researchers defined the objectives, hypothesis, and methodology for a parametric sensitivity analysis on the BN+GIS Model used for Risk Assessment on the Barnett Shale. Additionally, researchers developed an investigation about commercially available simulators (software) used for estimating production in unconventional reservoirs.

Keywords: Bayesian Networks, Risk Assessment, GIS, Environmental Impact

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Impact of the Gulf Intracoastal Waterway (GIWW) on Freight Flows in the Texas-Louisiana Megaregion

Robert Harrison, June 2015

This report addresses the benefits of maintaining the GIWW both in totality (5 States) and specifically between Texas and Louisiana since their coastal regions have been identified as a potential U.S megaregion. The chapters include a historical background and current conditions, the opportunities for raising barge productivity and safety, the challenges of increasing GIWW funding, the introduction of articulated tug barges (ATBs) which may have diverted some GIWW traffic, and finally summaries both findings and recommendations. It argues for sharply focused improvements and protecting system integrity for future technologies and barge designs.

Keywords: GIWW, Megaregions, Coastal Waterways, Articulated Tug Barges, Freight Systems, Jones Act

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Arterial Signal Coordination with Uneven Double Cycling

Hongmin Zhou, January 2015

In arterial coordination, high traffic volume at large intersections often requires a long cycle length to achieve good two-way progression. This long cycle length, however, often causes excessive delay at some minor intersections where the traffic volume is low on cross streets. This research proposes a mathematical optimization model to enable uneven double cycling (UDC) in arterial signal coordination to address this issue. The model presents an equation for delay estimation when using double cycling and formulated a bi-objective optimization problem that maximizes bandwidth efficiency and minimize total average delay. The model introduces the concept of nominal red to describe the bandwidth geometry that is compatible with conventional arterial coordination. Through disjunctive programming techniques, the resultant model is a mixed integer quadratic programming problem with linear constraints. Based on numerical experiments evaluating the model performance, the research suggests several criteria for preliminary UDC application guidance. The UDC control scheme generally performs better at intersections with permitted left turn operation. When the arterial green time ratio between the minor intersection and the critical intersection under single cycling is greater than 2.06, the UDC control scheme is recommended for it can reduce delay without reducing bandwidth efficiency when compared with conventional single cycling. Following the preliminary guidelines, the case study using an actual field dataset showed promising results.

Keywords: Traffic Signals, Optimization, Progression, Coordination

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Changing Perceptions of Cycling in the African American Community to Encourage Participation in a Sport that Promotes Health in Adults

Adriana Torcat, Talia McCray, and Teri Durden, June 2015

This study introduces two interventions designed to influence perceptions of cycling among African Americans. Results from the 2001 National Household Transportation Survey reveal that African Americans cycle at two-thirds the rate of White and Hispanic Americans (Pucher and Renne, 2003). Moreover, African Americans are less likely to possess alternative transportation modes like a bicycle (Royal and Miller-Steiger, 2008). Researchers suggest that cycling disparities are linked to negative perceptions among inexperienced cyclists and non-cyclists –including African Americans (McCray et al, 2010). An important consideration in analyzing why African Americans generally do not cycle is that of perception. The purpose of this study is to address negative perceptions of cycling that inhibit bicycle use, including a lack of experience, knowledge, and safety. Few studies exist that explore race or ethnic-specific reasons for low levels of physical activity and this information is needed to increase physical activity among minority groups (Rogers, et al. 2007). By examining perceptions of cycling among African Americans, this study builds on existing literature and fills a significant void in addressing the lack of bicycle ridership in the African-American community.

Keywords: Cycling, African American, Intervention, Safety-Training, Analysis of Means, AOM, Exploratory Factor Analysis, EFA

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The Impact of the Conversion of Incandescent Bulbs to the LED Light Source in Traffic Signals in Houston: A Step toward Sustainable Control Devices

Khosro Godazi, Alexandra Miller, Ronald E. Goodwin, June 2015

With the slowing of the American economy since 2008, it has become imperative that municipalities identify areas in which costs can be reduced while still providing needed services to its constituents. The use of traffic signals equipped with light emitting diodes (LED) provides opportunities for urban municipalities to conserve both tax dollars and energy. With other advantages, such as the reduced maintenance, a longer life span, and more illumination than the standard incandescent light bulb, LED’s have become a viable option in cities around the globe as a first step in reducing municipal costs. Furthermore, LED traffic signals could be retrofitted to solar energy in the future thereby enhancing the move towards “green” technologies. The City of Houston is the focus of this case study evaluating the use of LED traffic signals at selected intersections in and near the urban core.

Keywords: Conversion, Incandescent Bulbs, LED Light

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Calibration of the Louisiana Highway Safety Manual

Bridget Robicheaux and Brian Wolshon, February 2015

The application of the American Association of State Highway and Transportation Officials’ (AASHTO) Highway Safety Manual (HSM) to Louisiana roads is a key component to the Louisiana Department of Transportation and Development’s (DOTD) plan to improve safety on state highways and reach the goal of Destination Zero Deaths. The goal of this project was to develop Louisiana state-specific HSM calibration factors for eight facility types. During the completion of the project, the data-intensive computational process undertaken to compute the calibration factors revealed numerous issues associated with the input data required by the HSM. These included, most notably, coding errors and missing required data elements in the Louisiana roadway and crash databases. Some of the resulting factors were unexpected, in particular, those for urban three lane and urban five lane highways which were lower than anticipated. These factors may warrant further analysis beyond which was required for this project, including detailed assessments of each crash report to ensure data accuracy. The remaining calibration factors for rural two lane, rural multilane undivided and divided, urban/suburban two lane, and urban/suburban four lane divided and undivided highways, ranged from a low of 0.62 for rural multilane undivided highways to a high of 2.54 for urban/suburban four lane divided highways. It is expected that with an understanding of the conditions under which these factors were developed, that they will be acceptable for use by analysts seeking to conduct highway safety analyses for roads in Louisiana.

Keywords: Highway Safety Manual, Calibration, Crash, Crash Modification Factor, Safety Performance Function

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Assessment of the Effectiveness of Wrong Way Driving Countermeasures and Mitigation Methods

Melisa D. Finley, Steven P. Venglar, Vichika Iragavarapu, Jeffrey D. Miles, Eun Sug Park, Scott A. Cooner, and Stephen E. Ranft , December 2014

This report describes the methodology and results of tasks performed to evaluate the effectiveness of wrong way driving countermeasures and mitigation methods. Researchers reviewed the state of the practice regarding wrong way driving in the United States and Texas. Based on Texas crash data from 2007 through 2011, the majority of wrong way driving crashes on controlled-access highways occur in major metropolitan areas at night between midnight and 5:00 a.m. Driving under the influence was the primary contributing factor.

Therefore, researchers designed and conducted two closed-course studies to determine the effectiveness of select wrong way driving countermeasures on alcohol-impaired drivers. In addition, researchers obtained data from several Texas agencies that had installed wrong way driving countermeasures and/or mitigation methods on their road network. Using these datasets, researchers assessed the effectiveness of these strategies in actual operational environments. Researchers used the findings from these studies to develop recommendations regarding the implementation of wrong way driving countermeasures and mitigation methods.

Researchers used the focus group discussion method to obtain motorists’ opinions regarding the design of wrong way driver warning messages. Researchers also reviewed previous literature and message design manuals to gain insight into the design of wrong way driver warning messages that could be posted on dynamic message signs. Based on the findings, researchers developed two single-phase wrong way driver warning messages for dynamic message signs.

Keywords: Wrong Way Driving, Wrong Way Countermeasures, Wrong Way Detection Systems, Dynamic Message Signs, Impaired Driving

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A Novel Approach to Modeling and Predicting Crash Frequency at Rural Intersections by Crash Type and Injury Severity Level

Jun Deng, Marisol Castro, and Chandra R. Bhat, April 2015

Safety at intersections is of significant interest to transportation professionals due to the large number of possible conflicts that occur at those locations. In particular, rural intersections have been recognized as one of the most hazardous locations on roads. However, most models of crash frequency at rural intersections, and road segments in general, do not differentiate between crash type (such as angle, rear-end or sideswipe) and injury severity (such as fatal injury, non-fatal injury, possible injury or property damage only). Thus, there is a need to be able to identify the differential impacts of intersection-specific and other variables on crash types and severity levels. This report builds upon the work of Bhat et al. (2014) to formulate and apply a novel approach for the joint modeling of crash frequency and combinations of crash type and injury severity. The proposed framework explicitly links a count data model (to model crash frequency) with a discrete choice model (to model combinations of crash type and injury severity), and uses a multinomial probit kernel for the discrete choice model and introduces unobserved heterogeneity in both the crash frequency model and the discrete choice model. The results show that the type of traffic control and the number of entering roads are the most important determinants of crash counts and crash type/injury severity, and the results from our analysis underscore the value of our proposed model for data fit purposes as well as to accurately estimate variable effects.

Keywords:  Spatial Econometrics, Multiple Discrete-continuous Model, Random-coefficients, Land Use Analysis, MACML Approach

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Use of Infrared Thermography to Detect Thermal Segregation in Asphalt Overlay and Reflective Cracking Potential

Mostafa A. Elseifi and Nirmal Dhakal, March 2015

The objectives of this study were to assess whether temperature differentials measured using Infrared Thermography (IRT) occur in an overlay built on top of discontinuities such as joints and cracks and to study the horizontal and vertical thermal profiles in the asphalt overlay using a validated Finite Element (FE) modeling approach. To achieve this objective, an infrared camera was used to monitor the temperature profiles in the asphalt mat in a number of field projects from the time it was placed to after completion of the compaction process. The temperature profiles were monitored on top and away of severe discontinuities and joints in the existing pavement. Results showed that thermal measurements on top of the joints were consistently lower than away from it, which may indicate that temperature loss may occur at the joints. Further, a validated FE model predicted a slightly higher rate of thermal loss at the bottom of the overlay above the joint than away from it due to convection losses at the joint. While this difference may not be large enough to be identified as thermal segregation, it can influence the bulk properties of the overlay at the joints and promote early cracking. Thermal differences were also observed in the vertical direction as lower temperatures were predicted at the top and the bottom of the overlay during construction due to convection losses with the ambient atmosphere and conduction between the hot overlay and the existing pavement.

Keywords: Infrared Thermography, Temperature Segregation, Finite Element

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Identifying the Local and Regional Travel Effects of Activity Centers in the Austin, Texas Area

Ming Zhang, Wenjia Zhang, and Hao Pang, February 2015

Metropolitan planning organizations (MPOs) have become increasingly interested in incorporating innovated land use planning and design into transportation plan-making. Many design ideas are recommended under the umbrella of the New Urbanism; yet in practice they hardly get fully implemented in the standard transportation planning procedures. The project includes two parts. Part one refines the analysis of trip generation as it relates to mixed use development (MXD), with a focus on trip-chaining behavior, an approach taken by CAMPO. Part two looks into the potential of and challenges facing land use intervention as an emission reduction tool. Through the Austin case study, it investigates the regional and local distributional effects of vehicle miles traveled (VMT) and Green House Gas (GHG) emission changes pertaining to recommended land use and design innovations.

Keywords: Activity Centers, Land Use, Travel Demand, Emissions, Austin TX

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Accessing the Mega-Region: Evaluating the Role of Livable Community Patterns in Gulf Coast Mega-Region Planning

Billy Fields, March 2015

This research analyzes both the need and mechanisms for integrating livability components such as transit and active transportation into a broader mega-regions transportation framework. The research builds a conceptual framework for understanding how transportation livability concepts fit within the larger mega-regions literature. This framework based around the study of regional green infrastructure greenbelt systems is then used to analyze key strategies that could be integrated into the larger Gulf Coast/Texas mega-region transportation planning framework through analysis of three case studies in greater Houston, Austin/San Antonio, and New Orleans/Baton Rouge regions. Major existing and emerging opportunities to tie infrastructure into a mega-region transportation system are identified in these three case studies.

Keywords: Megaregions, Greenways, Trails, Active Transportation

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Nondestructive Test Methods for Rapid Assessment of Flexible Base Performance in Transportation Infrastructures

Hakan Sahin, August 2014

Well-built roads with longer service life and lesser life cycle cost are the key to meet the desired target of satisfying the public without compromising the quality of roads. Roads that are constructed and built with poor quality materials and inadequate design considerations frequently require costly maintenance and rehabilitation often resulting in detours and lane closures, which not just reduce the comfort of the public but also interrupt the efficient flow of transporting goods, and hence the associated businesses. Therefore, it is imperative that alternative quality control and quality assurance methods along with effective test methods and smart transportation planning must be considered and implemented to help communities increase the economic prosperity while retaining and ensuring a high quality of life to the people.
The appropriate application of reliability to pavement design is essential to achieve the main objectives of designing quality pavements to serve the traveling public with comfort and safety while being durable in service at a minimum life cycle cost.
The quality of the base layer of the pavement, which is located directly beneath the surface, is one of the most critical components in designing a pavement with increased service life and durability. The base layer is primarily composed of aggregates and contributes to the structural stability of the pavement system by providing load transfer and support. A base course with adequate thickness and built with high quality aggregates is essential to meet the necessary performance criteria and in doing so will cut down on reconstruction cycles and cost of maintenance.
This research attempts to contribute in this regard by evaluating the significance of using the fundamental material properties to develop models which characterize the base layer in a pavement system. These new models will have significant contributions to soil mechanics and highway design procedures. This research and the developed models depend upon fundamental soil properties. This work capitalizes upon the fundamental properties to make extensive use of these models for quality control (QC) and quality assurance (QA), in the pre-design procedure and construction phase. The most significant impact of the work is to replace and improve current methods, increase work efficiency, minimize time spent in the laboratory, find more convenient relationships, reduce costs, and improve sustainability. In addition, the quickly and accurately measured aggregate characteristics of base courses will be used to determine the in-place and as-compacted design properties for QC and QA.

Keywords: Material Properties, Pavement Design, Flexible Base Course, Aggregate Characteristics, Quality Control, Performance

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1990 Transportation Engineering Research Reports

Daniel B. Fambro, Editor, 1991

The engineering research reports in this document resulted from the first year of the Undergraduate Transportation Engineering Fellows Program during the summer of 1990. The ten-week program, sponsored by the Advanced Institute program of the Southwest Region University Transportation Center (SWUTC), the Texas Transportation Institute (TTI), and the Civil Engineering Department at Texas A&M University, provides undergraduate students in Civil Engineering with the opportunity to learn more about transportation engineering through participating in a transportation research program. The program design allows the students to interact directly with a faculty member or TTI researcher in developing a research proposal, conducting appropriate research, and documenting the research results.

The papers in this compendium report on the following topics: 1) Two-Exit Directional Freeway Interchanges, 2) Analysis of the Southwest Freeway Reconstruction Project, 3) Merge Behavior at Entrance Ramp Junctions, and 4) Urban Traffic Management.

Mentors: Thomas Urbanik II, Raymond A. Krammes, Daniel B. Fambro, and H. Gene Hawkins.

Keywords: Congestion, Freeway Design, Traffic Management, Freeway Operations, Freeway Reconstruction

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The Effect of the City of Houston Transit Corridor Ordinance on Development along METRO’s Light Rail Corridors

Walter Hassell, Carol Abel Lewis, and Jennifer Auzenne, October, 2014

Many cities are moving toward more compact, transit friendly development. Specifically when the focus of the development is the transit, the concept is considered transit friendly and termed transit supportive or transit oriented development. Typically rail stations or transit centers spawn medium to high density mixed-use developments, designed to promote walking, transit and bicycling in those areas.. It is common for cities to revise codes and guidelines to encourage transit friendly development. The City of Houston’s development, public infrastructure and built environment are guided by the Chapter 42 Subdivision, Developments, and Platting Ordinance.

In 2009 the City of Houston added a Transit Corridor Ordinance, a code in Chapter 42 to encourage an urban environment that improves pedestrian mobility, supports METRO’s light rail investment, and helps accommodate the City’s anticipated growth. This research examines developer response to the Transit Corridor Ordinance and determines which parcels owners have chosen to undertake design of elements within this code. Other agency TOD efforts, various developer rail station projects and best practices of public and private joint developments are also explored.

Keywords: Transit Supportive Development, City Policy and Transit Oriented Development

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Productivity-based Approach to Valuation of Transportation Infrastructure

Zhanmin Zhang and Diniece D. Peters, October, 2014

Transportation infrastructure, a vital component to sustain economic prosperity, represents the largest public-owned infrastructure asset in the U.S. With over a trillion invested dollars invested into long-lived physical assets such as roads and bridges, transportation agencies are tasked with maintenance and rehabilitation efforts to ensure that the access to transportation facilities is readily available and that the infrastructure is properly preserved. The management of these assets and the determination of their value, however, have been at the forefront of discussions in many state agencies and local governments. As a consequence, asset valuation has become a key component in asset management because it links the performance of infrastructure and deterioration process with the value of the infrastructure and its depreciation, providing critical information for decision makers at various levels to make more informed decisions. A utility-based methodological framework for the valuation of transportation infrastructure is presented along with a case study to demonstrate its applicability. A general framework is presented with emphasis on the valuation of pavement infrastructure. The results from the framework is then compared to existing valuation methods in addition to a series of sensitivity analysis on the variation of performance measures and their effect on the value of an asset. The development of this valuation approach serves as a starting point for assessing, in addition to the physical condition of an asset, the operational measures that can often make an asset less useful to its customers and managing agency. Utility theory can be utilized to combine the effect of performance indicators of varying measures and scales on the value of an asset. The proposed framework can assist state and local transportation agencies in the optimization of resource allocation procedures for better coordination of asset investments, facilitating benefit-cost analyses to quantify the impact of infrastructure investments. This tool allows agencies to detect deficiencies if any, in the management of its assets, providing a feedback mechanism that can foster an introspective review of its current management practices that may need further refinement or possibly elimination.

Keywords: Infrastructure, Maintenance, Rehabilitation Efforts, Asset Valuation, Asset Management, Utility Theory, Resource Allocation, Benefit-Cost Analysis

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Examining the Market Potential for Natural-Gas-Powered Trucks: Barriers and Opportunities for Promoting Environmental Sustainability and Economic Prosperity

Ryan Hazlett and Lauren Cresswell, August, 2014

Over the past decade, public concerns have grown over America’s energy use and production. Pushes towards more environmentally friendly and sustainable sources of energy have moved out of fringe politics and into mainstream political discourse. Advances in drilling technology and increased exploration of shale gas plays have made natural gas more available and accessible. The abundance of natural gas has led to its growing role in the U.S. electric production and has provided the United States with an opportunity to become a net exporter of energy in the near future. The availability of natural gas, coupled with uncertainty in the liquid petroleum market, has prompted stakeholders to search out additional uses for this low-cost energy source. The result has been a large-scale effort to encourage the use of natural gas-based fuel within the trucking industry. Commercial long-haul trucks and truck fleets are a prime target of these efforts. The number of natural gas fueling stations around the country is increasing, and there are growing investments in new technologies and government incentives to retrofit and upgrade the nation’s trucking fleet, making the logistics of a large-scale switch from a liquid petroleum-based fuel to natural gas much less complicated. Through a detailed analysis of natural gas trucks, fueling infrastructure, and case studies, this report seeks to reach conclusions over the role natural gas vehicles (NGVs) should play in the future U.S. transportation system.

Keywords: Natural Gas Vehicles, Natural Gas, Fueling Infrastructure, Long-Haul Heavy Trucks, State and Local Fleet Vehicles

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Fatigue and Fracture Properties of Aged Binders in the Context of Reclaimed Asphalt Mixes

Arash Motamed, Solomon Nyanhongo, Pravat Karki and Amit Bhasin, August, 2014

Evidence in the literature indicates that the stiffness of the asphalt binder increases and ductility of the binder decreases with oxidative aging. Typically for unmodified asphalt binders, increase in stiffness or decrease inductility is regarded as detrimental to the fatigue cracking or fracture resistance of the asphalt binder. However, fundamentally the stiffness of the binder and its strength are two different attributes that may not necessarily be related to each other. There is very little information in the literature that relates the fatigue cracking resistance or strength of the asphalt binder to the extent of oxidative aging. This information is not only important to assess the durability and cracking life of asphalt pavements but is also very important in the context of reclaimed asphalt pavements (RAP). The use of RAP not only reduces the waste produced from milling and removing the asphalt pavement layers at the end of their service life, but also reduces the amount of asphalt required for the construction of new roadways. In an effort to improve sustainable practices associated with pavement constructions, state DOTs have been gradually increasing the allowable percentage of RAP in new asphalt mixtures over the last two decades. However, the asphalt binder in RAP is highly oxidized and is deemed to be susceptible to load related fatigue cracking. The focus of this study was to investigate the effect of asphalt binder oxidation on its fracture properties and fatigue cracking performance. To this end, fatigue cracking resistance of an asphalt binder was measured at different levels of aging using a standardized glass bead composite. The glass bead composite simulates the stress state that asphalt binders experience in the field, while it excludes aggregate-asphalt binder interactions. Furthermore, this research also investigated the effect of aging on fracture properties of an asphalt binder by conducting monotonic fracture tests using a poker chip test geometry. The findings from this study provide a better understanding of the effect of aging on the fracture and fatigue properties of asphaltic materials.

Keywords: Reclaimed Asphalt Pavements, RAP, Oxidation, Oxidative Aging

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Executive Report: Toll Roads, Toll Rates, and Driver Behavior

Curtis Beaty, Mark Burris, and Tina Geiselbrecht, July, 2013

State and federal research has examined toll roads and attempted to identify methods to make toll roads a more attractive option for drivers. Researchers examined various views of toll road transactions and concluded:

• Truckers and trucking companies view toll roads significantly differently than the average passenger car driver. Travel time savings and avoiding congestion are generally less important than the actual cost of the tolls and their inability to pass those costs to their customers.
• Drivers require more information on toll roads: where they are located, how/where to access them,how to pay for the toll transaction, how much time will they save by taking a toll road versus a free alternative, who operates a given toll road, etc.
• Raising toll rates actually increases revenue while lowing toll rates will increase traffic volumes at the expense of toll revenues.

Keywords: Toll Roads, Toll Rates, Traffic Volume, SH 130

ENTIRE REPORT (Adobe Acrobat File – 306 KB)

Performance and Cost Effectiveness of Permeable Friction Course (PFC) Pavements

Edith Arámbula, Cindy K. Estakhri, Amy Epps Martin, Manuel Trevino, André de Fortier Smit, and Jorge Prozzi, February, 2013

In this project, the research team evaluated the performance of Permeable Friction Courses (PFC) over time and compared it against other types of wearing surface pavement layers. Several pavement sections including Asphalt Rubber (AR) PFCs, Performance Graded (PG) PFCs, and dense-graded Hot Mix Asphalt (HMA) were monitored over a four-year period. Non-destructive on-site measurements included noise, drainability, texture, friction, and skid. The change of these variables with time as well as the influence of traffic, binder/mixture type, aggregate classification, and climatic region was evaluated. Accident data were also gathered and analyzed on a more comprehensive number of pavement sections across Texas. All of this information was compiled in database format. In addition, when performance issues were identified, field cores were acquired for forensic evaluation. Results from the multiyear performance data analysis and previous research were used to produce guidelines and recommendations to improve the design, construction, and maintenance of PFCs.

Performance of PFCs over time was adequate. Therefore, the continued use of PFCs in Texas is encouraged. PFCs had lower overall noise levels when compared to dense-graded HMA, and AR-PFCs were quieter than PG-PFCs. With regard to drainability, the water flow values had a tendency to increase early in the life of the pavement and remain relatively constant afterward. PG-PFCs showed better drainability as compared to AR-PFCs. The amount of rainfall helped assure the continued drainability of PFCs, especially in warm climates. Texture for PFCs remained practically unchanged over time. Both AR- and PG-PFCs had superior texture and skid vs. dense-graded HMA pavements. With regard to friction and skid, sections with aggregates classified as SAC-B per the Surface Aggregate Classification (SAC) system had statistically significantly lower values as compared to those pavement employing either SAC-A or SAC-A/B aggregates. The accident data indicated that PFCs reduce the number of accidents, injuries, and fatalities on roads in Texas.

Keywords: Porous Friction Course, Open-Graded Friction Course, Porous Asphalt, Mixture Performance, Asphalt Mixture Permeability, Noise Reduction

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A Methodology to Support the Development of 4-Year Pavement Management Plan

Nasir G. Gharaibeh, Paul Narciso, Youngkwon Cha, Jeongho Oh, Jose Rafael Menendez, Samer Dessouky, and Andrew Wimsatt, July, 2014

A methodology for forming and prioritizing pavement maintenance and rehabilitation (M&R) projects was developed. The Texas Department of Transportation (TxDOT) can use this methodology to generate defensible and cost-effective 4-year pavement management plans (PMPs). The developed methodology was implemented in a web-based software tool for evaluation by TxDOT personnel. This tool can potentially be used in the future by TxDOT to generate 4-year PMPs for individual districts and the statewide network. Key components of this methodology are:

• Methods for grouping data collection sections into pavement management sections (potential M&R projects).
• Pavement performance prediction models.
• Methods for measuring performance benefits and life-cycle costs of alternative M&R types and projects.
• A method for prioritizing competing M&R projects using an incremental benefits-cost analysis.
• Analysis of the impact of funding scenarios on network condition throughout the planning period.

Projects are prioritized considering multiple factors that are deemed important by TxDOT’s districts. These factors and their importance weights were identified using a web-based survey of TxDOT’s districts. The methodology was tested and validated for Bryan, Fort Worth, and Lubbock Districts. The results highlight the potential of the developed methodology to improve pavement management planning by incorporating district priorities, producing cost-effective pavement management plans, and providing insights into the impact of these plans on the network condition.

Keywords: Pavement Management, Pavement Performance Prediction, Maintenance and Rehabilitation Planning, Project Prioritization

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Performance Testing of Coagulants to Reduce Stormwater Runoff Turbidity

Jett McFalls, Young-Jae Yi, Beverly Storey, Michael Barrett, Desmond Lawler, Brad Eck, David Rounce, Ted Cleveland, Holly Murphy, Desirae Dalton, Audra Morse, and George Herrmann, May, 2014

On December 1, 2009, the US Environmental Protection Agency (EPA) published a rule in the Federal Register establishing non-numeric and, for the first time, numeric effluent limitation guidelines (ELGs). The numeric ELGs included a turbidity limit of 280 nephelometric turbidity units (NTU) and sampling requirements for stormwater discharges from construction sites that disturb 20 or more acres of land at one time. At that time, the EPA required Texas to implement these new requirements when the Texas Commission on Environmental Quality (TCEQ) renewed their Texas Construction General Permit (CGP) in 2013. Due to litigation regarding the initial numeric ELG implementation, the EPA put numeric ELGs on hold in 2011 and on April 13, 2013, proposed to withdraw the numeric ELG as a requirement.

This project was initiated in 2010 to prepare the Texas Department of Transportation (TxDOT) for changes to the CGP regarding the monitoring and sampling of their construction site to meet the anticipated numeric ELG requirements. The scope of the project was modified due to EPA’s actions. However, in light of anticipated future numeric limits, the project’s monitoring and testing experiments proceeded to 1) determine “typical turbidity” representative of TxDOT’s construction site discharges, 2) collect performance data on innovative erosion and sediment control measures that might be expected to achieve the discharge standard, and 3) provide update to TxDOT’s Stormwater Managements Guidelines for Construction Activities.

Keywords: Effluent Limitation Guidelines, Stormwater, Turbidity, Flocculants, Coagulants, ELG, Erosion Control, Sediment Control

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Characteristics of Texas Pedestrian Crashes and Evaluation of Driver Yielding at Pedestrian Treatments

Kay Fitzpatrick, Vichika Iragavarapu, Marcus A. Brewer, Dominique Lord, Joan Hudson, Raul Avelar, and James Robertson, May, 2014

For Texas, the average number of pedestrian fatalities for 2007 to 2011 is about 400 per year. Due to the high number of pedestrian crashes, Texas is considered by the Federal Highway Administration (FHWA) to be a “focus” state. Researchers found that 2 percent of all Texas Department of Transportation (TxDOT)-reportable traffic crashes and 15 percent of all TxDOT-reportable fatal crashes were pedestrian related. Most non-fatal crashes are associated with daylight, at intersections, and on city streets, whereas most fatal crashes are associated with dark conditions, midblock locations, and high-speed roadways. Twenty-one percent of all fatal TxDOT-reportable pedestrian crashes occurred on freeways—a location where pedestrians are least expected. Additional research into how to address pedestrian crashes, especially freeway crashes, is needed, perhaps using FHWA’s new systematic safety project selection tool. In the past decade, the pedestrian hybrid beacon (PHB) and rectangular rapid-flashing beacon (RRFB) have shown great potential in improving driver yielding rates and conditions for crossing pedestrians. Researchers conducted a field study at 7 traffic control signal (TCS) sites, 22 RRFB sites, and 32 PHB sites in Texas with the effectiveness measure being the percent of drivers yielding to a staged pedestrian. Results showed that driver yielding rates varied by type of treatment. Overall, TCSs in Texas have the highest driver yielding rates (98 percent), followed by PHBs (89 percent) and RRFBs (86 percent). Those cities with a greater number of a particular device (i.e., Austin for the PHB and Garland for the RRFB) had higher driver yielding rates as compared to cities where the device was only used at a few crossings. Also, as drivers became more familiar with the PHB, a greater proportion yielded, perhaps because they gained a better understanding of expectations or requirements over time. As part of this study, researchers conducted a before-and-after field study at four RRFB sites and one PHB site to identify the changes in driver yielding and selected pedestrian behaviors resulting from installing these treatments at previously untreated crosswalks. The installations resulted in noticeable improvement in the number of yielding vehicles.

Keywords: Pedestrian Crashes, Pedestrian Treatments, Funding, Pedestrian Hybrid Beacon, Rectangular Rapid-Flashing Beacon

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Evaluating the Need for Surface Treatments to Reduce Crash Frequency on Horizontal Curves

Michael P. Pratt, Srinivas R. Geedipally, Adam M. Pike, Paul J. Carlson, Amelia M. Celoza, and Dominique Lord, May, 2014

The application of high-friction surface treatments at appropriate horizontal curve locations throughout the state has the potential to improve driver performance and reduce the number of crashes experienced at horizontal curves. These treatments must be implemented judiciously due to their cost, but have the potential to improve safety at lower cost than geometric improvements like curve straightening, and with greater effectiveness than control-device treatments like installing delineators or Chevrons.

An analysis framework has been developed to assess the need for surface treatments at curves based on the concept of margin of safety analysis. Models have been developed to predict vehicle speeds throughout a curve, and calibrated using data from Texas curve sites. Safety prediction models have also been developed to quantify the relationship between skid number and curve crash frequency. This information can be applied to evaluate the safety performance of a curve of interest and estimate the potential safety benefit of installing a high-friction surface treatment.

Keywords: Highway Design, Highway Safety, Rural Highways, Highway Curves, Speed Measurement, Traffic Speed

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Maximizing Mitigation Benefits–Making a Difference with Strategic Inter-resource Agency Planning: Year One Technical Report

John H. Overman, Beverly Storey, Edgar Kraus, Kristi Miller, John Walewski, Zachary Elgart, and Sam Atkinson, April, 2014

The objective of this research project is to assess current mitigation policies and practices in comparison to resource agency objectives, and identify mitigation strategies and priorities that provide greater cost-benefit potential and implementation speed through strategic inter-resource agency planning. Mitigation for various actions associated with transportation development has been part of the process for decades. Although the science, practice, and technology may have advanced during this time, many of the processes and practices are rooted in traditional rules and regulations that require mitigation. The objective for this project is to assess mitigation policies and practices as a whole–looking at both the current and future of mitigation efforts in the transportation development process. This report summarizes activities conducted in the first year of the project.

Keywords: Mitigation, In-Lieu Fee Mitigation, Watershed Planning, Wetland Mitigation Banks, Greenprinting, Consolidated Mitigation Projects, Mitigation Credit, Permittee-Responsible Mitigation, Special Area Management Plans

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HMA Shear Resistance, Permanent Deformation, and Rutting Tests for Texas Mixes: Year-1 Report

Lubinda F. Walubita, Sang Ick Lee, Jun Zhang, Abu NM Faruk, Stan Nguyen, and Tom Scullion, April, 2014

Traditionally run at one test temperature (122°F), the Hamburg Wheel Tracking Test (HWTT) has a proven history of identifying hot-mix asphalt (HMA) mixes that are moisture susceptible and/or prone to rutting. However, with the record summer temperatures of the recent years, several shear and rutting failures have occurred with HMA mixes that had passed the HWTT in the laboratory; mostly in high shear locations, in particular with slow moving (accelerating/decelerating) traffic at controlled intersections, stop-go sections, in areas of elevated temperatures, heavy/high traffic loading, and/or where lower PG asphalt-binder grades have been used.

As a supplement to the HWTT, this two-year study is being undertaken to develop a simpler and less time consuming shear resistance and permanent deformation (PD)/rutting test that is also cost-effective, repeatable, and produces superior results in terms of correlation with field rutting performance. In particular, such a test should have the potential to discriminate HMA mixes for application in high shear stress areas (i.e., intersections) as well as being an indicator of the critical temperatures at which a given HMA mix, with a given PG asphalt-binder grade, becomes unstable and more prone to rutting and/or shear failure.

In line with these objectives, this interim report documents the research work completed in Year-1 of the study, namely: a) data search and literature review; b) computational modeling and shear stress-strain analysis; c) comparative evaluation of the Asphalt Mixture Performance Tester (AMPT) and the Universal Testing Machine (UTM); d) comparative evaluation of the Flow Number (FN), Dynamic Modulus (DM), and Repeated Load Permanent Deformation (RLPD) tests relative to the HWTT test method.

Keywords: HMA, Rutting, Shear, Permanent Deformation (PD), Stress, Strain, Visco-elastic, Hamburg (HWTT), UTM, AMPT, Flow Number (FN), Dynamic Modulus (DM), Repeated Load Permanent Deformation (RLPD), Finite Element (FE), Shear Strength, Modulus

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Literature Review: Performance of RAP/RAS Mixes and New Direction

Fujie Zhou, Cindy Estakhri, and Tom Scullion, April, 2014

In the last several years reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been widely used in asphalt mixes in Texas. The use of RAP/RAS can significantly reduce the initial cost of asphalt mixtures, conserve energy, and protect our environment. There are always two main concerns: variability of RAP/RAS and durability (or cracking) of RAP/RAS mixes. Past studies in Texas have clearly indicated that both RAP and RAS have acceptable variability following the best practices for handling RAP/RAS. This study will focus on the durability of RAP/RAS mixes. This report presents a review of using RAP/RAS in asphalt mixes, the identified research focus, and the revised field experimental test plan.

Specifically, this report discusses the field performance of RAP/RAS mixes in Texas and other states, and the observed field performance data strongly support the necessity of establishing a RAP/RAS mix design system for project-specific service conditions. The best practices for using RAP/RAS in hot-mix asphalt (HMA) and warm mix asphalt (WMA) mixtures, including RAP/RAS processing, mix design, production, and field construction, are also documented. Additionally, the new specification for asphalt mixes in Texas is reviewed and then a revised field experimental test plan for validating the new specification is recommended.

Keywords: Reclaimed Asphalt Pavement, Recycled Asphalt Shingles, Asphalt Mix Design, Field Performance

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A Hot Spot Analysis of Teenage Crashes: An Assessment of Crashes in Houston, Texas

Gwendolyn C. Goodwin, Jamaal Schoby, and Walter Council, September, 2014

Today, states have enacted laws to ensure that teen drivers are more skilled and drive safely. The result is fewer accidents. However, in previous research, when teen crashes were mapped, certain streets and areas appeared to have more accidents than other areas. The goal of this research is to investigate the “hot spot” locations where teens have accidents and to determine important factors contributing to the concentration of accidents. This research will benefit planners and engineers and help them determine if additional changes are needed at locations with high teen crashes to make these areas safer.

Keywords: Teen Accidents, Hot Spot Analysis, Young Drivers

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Cost-Efficiency of Highway Operations and Maintenance of Public-Private Partnerships

Sergio E. Martinez and C. Michael Walton, August, 2014

While the literature on public-private partnerships (PPPs) argues that the private sector’s life-cycle approach to design and construction results in operational cost efficiencies, empirical support is missing. This study explored that issue by conducting a four-prong investigation. First, a literature review searched for evidence of such efficiencies and methodologies to evaluate them: it found no empirical evidence of superior operations and maintenance (O&M) cost-efficiency in PPPs. Second, a simple methodology to evaluate life-cycle cost-efficiency is proposed, but adequate data and assumptions about O&M costs are needed. Third, since PPP projects in the U.S. are recent and currently subject to routine O&M, indicators to compare those costs were proposed as well. Fourth, a case study compared the routine O&M costs of a PPP to those of a system of traditionally delivered toll roads. The results showed that the PPP was more cost-efficient in operating expenditures (OPEX) per mile (-60%) and per lane-mile (-53%). The traditional system was more cost-efficient in OPEX per vehicle miles travelled (97%), toll transactions (332%), and toll revenue (20%). However, those three indicators depend on traffic volumes, which were overwhelmingly greater on the traditional system. While the case study showed cost-efficiency differences between public and private sectors, additional research is needed to empirically test the hypothesis of the private sector’s greater efficiency. Understanding the differences in cost-efficiency between publicly and privately managed roads will help decision-makers to minimize the life-cycle cost of their investments.

Keywords: Public-Private Partnerships, PPPs, Transportation, O&M, Efficiency

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The Future of Fully Automated Vehicles: Opportunities for Vehicle- and Ride-Sharing, with Cost and Emissions Savings

Daniel Fagnant and Kara Kockelman, August, 2014

Fully automated or autonomous vehicles (AVs) hold great promise for the future of transportation. By 2020 Google, auto manufacturers and other technology providers intend to introduce self-driving cars to the public with either limited or fully autonomous capabilities. AVs may be able to save the U.S. economy up to $37.7 billion in comprehensive costs from safety, mobility and parking improvements at the 10% market penetration, and potentially up to $447.1 billion with 90% market penetration. Even with only 10% market share, over 1,000 lives could be saved annually. However, realizing these potential benefits while avoiding potential pitfalls requires more than just technology advancements: significant barriers to a successful rollout include AV costs, liability, security, and privacy.

Once fully self-driving vehicles can safely and legally drive unoccupied on U.S. streets, a new transportation mode for personal travel looks set to arrive. This new mode is the shared automated vehicle (SAV), combining on-demand service with self-driving capabilities. This work simulates a fleet of SAVs operating within the city of Austin, using Austin’s transportation network and travel demand flows. This model incorporates dynamic ride-sharing (DRS), allowing two or more travelers with similar origins, destinations and departure times to share a ride.

Model results indicate that each SAV could replace around 10 conventionally-owned household vehicles while serving over 56,000 person-trips. SAVs’ ability to relocate while unoccupied between serving one traveler and the next may cause an increase of 4-8% more travel; however, DRS can result in reduced overall VMT, given enough SAV-using travelers willing to ride-share. SAVs should produce favorable emissions outcomes, with an estimated 16% less energy use and 48% lower volatile organic compound (VOC) emissions, per person-trip formerly served by a household vehicle.

Keywords: Autonomous Vehicles, Automated Vehicles, Car-Sharing, Ride-Sharing, Emissions

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Policy Implications of Emerging Vehicle and Infrastructure Technology

Peter J. Jin, Dan Fagnant, Andrea Hall, and C. Michael Walton, August, 2014

This report considers a broad range of emerging transportation technologies that have potential for enhancing travel on and operations of the Texas transportation system. It provides an overview of technology classifications and assesses the policy implications of emerging vehicle and infrastructure technology classifications—namely, connected, autonomous, and electric vehicle technologies—as well as cloud computing and crowdsourcing in the context of transportation systems and services. The researchers assessed these technologies in terms of their ability to further state and national transportation goals. Also assessed were barriers to adoption and promotion at various development stages. Research is presented on new policies and institutional changes that are being implemented outside of Texas. Finally, policy implications for Texas are discussed.

Keywords: Electric Vehicles, Fuel Tax, Finance, Revenues, Transportation Policy

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Use of Containers to Carry Bulk and Break Bulk Commodities and Its Impact on Gulf Region Ports and International Trade

James R. Amdal and Marc Howlett, August, 2014

The overall objective of this study is to assess the impact of all-water Asian service on ports along the U.S. Gulf Coast due to the Panama Canal Expansion (PCE) and the resultant growth of the container trade in these ports. The potential impacts on coastal, river, and inland ports in Louisiana are also assessed as they all may be affected. However, to put these specific impacts in context, the University of New Orleans Transportation Institute (UNOTI) first investigated the impacts of the PCE on shipping services and coastal port infrastructure along both the east and west coasts of North, Central, and South America, as well as the Gulf ports. A detailed spreadsheet of port specific actions and expenditures made in anticipation of the expansion of the Panama Canal is included as Appendix A. Impacts on selected ports and commodities, both imports and exports, have also been assessed based on historic performance and informed speculation to the year 2020. Secondly, UNOTI assessed the impact of new shipping services calling on Gulf ports. The researchers investigated both import and export commodities shipped by container and determined which commodities can grow in Louisiana ports and/or what measures must be taken in order for this growth to occur. A select Project Advisory Board, representing a broad cross section of transportation leaders in Louisiana from both the public and private sector, was convened to review the findings of this research project.

Keywords: Containerized Break and Break Bulk Commodities, Gulf Coast Ports, Panama Canal Expansion

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Controlling Conductivity of Asphalt Concrete with Graphite

Philip Park, Younho Rew, and Aishwarya Baranikumar, August, 2014

Electrically conductive asphalt concrete has a huge potential for various multifunctional applications such as self healing, self-sensing, and deicing. In order to utilize the full spectrum of applications of electrically conductive asphalt composites, precise control of the asphalt mixture resistivity is needed. Most of the previous research using conductive fibers as the primary conductive additives observed a sudden transition from the insulated to conductive phase, commonly known as the percolation threshold, which obstructs more precise conductivity control. Aiming to control the electrical conductivity of asphalt concrete with a smooth transition from the insulated to conductive phase, the researchers have selected graphite powders as an alternative conductive additive in this study. Nine types of graphite having different particle shape, size, and origin were mixed with asphalt binders, and their effects on imparting conductivity were investigated. Based on the results, the research team selected two types of graphite and evaluated the effects on the electrical conductivity of asphalt concrete. The team also examined the effects of aggregate gradation, binder content, and binder type.

The results showed that the electrical conductivity of asphalt mastic is sensitive to the graphite type. The natural flake graphite is effective to mitigate the percolation threshold, and a sufficiently high conductivity can be achieved by replacing a part of the fillers with graphite (the conductivity ranged from 10−6 to 10−2/Ω•cm). The results also showed that the binder type does not make a significant change in the mixture conductivity, but the aggregate gradation brings approximately two order differences in the volume resistivity. Mechanical performance of the conductive asphalt is also an important factor for practical field applications. The indirect tension test results showed that the addition of graphite improves the indirect tensile strength up to 41 percent. The electrical and mechanical data obtained from this study provide essential information on the selection of graphite type and asphalt mixture design to achieve the proper electrical conductivity required for the probable multifunctional applications of asphalt concrete, which will lead to technical innovations for sustainable pavements.

Keywords: Electrical Conductivity Control, Graphite, Asphalt Concrete, Percolation Threshold

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Regional Decision-Making and Competitive Funding: Metropolitan Planning Organizations and the Transportation Investments Generating Economic Recovery Program

Kate Lowe, August, 2014

Transportation benefits and economic stimulus were behind the creation of the Transportation Investment Generating Economic Recovery (TIGER) program in 2009. New transportation funding programs exist in a landscape of other programs, and in addition extensive federal rules require that state-designated metropolitan planning organizations (MPOs) lead regional transportation planning and produce near and long-range plans. This report examines the potential for the TIGER program to conflict with these mandated planning processes. To learn about the connection between MPOs, their planning documents, and TIGER applications, the primary dataset for analysis was a survey of metropolitan planning organizations. The roles that MPOs and their planning documents played in TIGER application processes were highly varied. While some MPOs were local project sponsors and others advised or provided data, a sizable share of MPOs reported no role in the regional process to select projects for TIGER applications, despite federally mandated regional coordination and planning. MPO capacity appears to differ significantly and to affect the roles that MPOs play in regional processes. While there are already additional planning requirements for larger urbanized areas, further differentiation of roles and expectations for MPOs may be appropriate. New programs, especially those with short time lines, may obscure the process for joint decision making and complicate adherence to regional planning mandates. Results on MPO roles and the relationship between plans and candidate projects suggest that MPOs are not always the decision site as language in plans would suggest, but they can be an important site for convening stakeholders.
 

Keywords: TIGER, Metropolitan Planning Organizations

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Incorporating Risk and Uncertainty into Pavement Network Maintenance and Rehabilitation Budget Allocation Decisions

Jose Rafael Menendez Acurio, August 2014

According to the American Society of Civil Engineers, 33% of the United States’ major roads are in poor or mediocre condition with a projected funding shortfall of $549.5 billion for 2010–2015. Environmental factors, increased traffic, and lack of adequate maintenance are causing many of these roads to deteriorate faster. The imbalance between maintenance needs and available funds tends to become more critical over time, demanding more reliable and advanced tools for allocating funds and prioritizing projects.

In 2012, the U.S. Congress passed the Moving Ahead for Progress in the 21st Century Act (MAP-21) to fund surface transportation programs for 2013–2014 and beyond. MAP-21 establishes a framework for federal transportation investments with the goals of preserving the highway system while improving its condition and performance. This law requires states to develop risk-based asset management plans that include risk management analysis. In order to fulfill MAP-21 requirements, pavement management systems must be upgraded to incorporate risk management, permitting pavement management systems to serve as a more realistic decision support tool for planning and budget allocation in pavement maintenance and rehabilitation.

This dissertation aims to incorporate risk assessment into maintenance and rehabilitation budget decisions at the planning stage. For risk assessment, uncertainty was incorporated into the analysis process, and factors influencing decisions are modeled as probability distributions. The factors included are pavement conditions, available funds, maintenance and rehabilitation costs, and performance prediction. The risk for each scenario is defined as the probability of failing to achieve pre-defined performance goals.

The results of this research show that the benefit-cost budget allocation method has the lowest risk to fail to achieve the performance goals. The maintenance-first method has slightly higher risk but averages scores are better compared with benefit-cost. The method with highest risk is the rehabilitation-first, which have a significant difference with all the other allocation methods.

This research demonstrates that incorporating uncertainty and risk assessment into pavement management can lead to better-informed decision and ultimately improved M&R budget allocation policies. This work provides DOTs with analytical tools and methods for meeting the requirements of MAP-21.

Keywords: Water Vapor Diffusion, Fine Aggregate Mixture, Pseudo Strain, Dissipated Pseudo Strain Energy, Surface Energy

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Next Generation Safety Performance Monitoring at Signalized Intersections Using Connected Vehicle Technology

Liteng Zha, Praprut Songchitruksa, and Kevin N. Balke, August, 2014

Crash-based safety evaluation is often hampered by randomness, lack of timeliness, and rarity of crash occurrences. This is particularly the case for technology-driven safety improvement projects that are frequently updated or replaced by newer ones before it is possible to gather adequate crash data for a reliable and defensible before-after evaluation. Surrogate safety data are commonly used as an alternative to crash data; however, its current practice is still resource intensive and subject to human errors. The advent of connected vehicle technology allows vehicles to communicate with each other and infrastructure wirelessly. This platform also offers the opportunity for automated and continuous tracking of vehicle trajectories and signal status at the facilities in real time. These types of data can potentially be extracted and used to detect the deficiencies in the safety performance of the facility operation.

This project examines the viability of long-term monitoring of connected vehicle data for safety performance evaluation. As limited saturation of onboard equipment (OBE) is expected in the near-term evolution, the study focuses on a connected vehicle application that can process data elements from OBEs via vehicle-to-infrastructure communications using standard message sets. To accomplish the objective, a signalized intersection test bed was created in VISSIM while the wireless communications capability and the application were implemented using Car-to-Everything Application Programming Interface. The evaluation results indicated that the application can effectively detect changes in safety performance at full market penetration. Sensitivity analysis showed that at least 40 percent penetration rate is desirable for reliable safety deficiency detection under light to moderate traffic volume conditions. The observation period can be extended to compensate for low sample size under low OBE market penetrations. The required observation periods vary with the types of safety indicators being collected and the levels of OBE saturation.

Keywords: Connected Vehicles, Traffic Simulation, Safety Evaluation, Surrogate Safety Measures, Wireless Communications, Traffic Conflicts, Market Penetration

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Enhanced Adaptive Signal Control Using Dedicated Short-Range Communications

Yunlong Zhang and Kamonthep Tiaprasert, May, 2014

Connected vehicle technology with dedicated short-range communications can provide traffic information in a spatial domain that conventional fixed-point detectors cannot provide. However, because of low market penetration with this new data source, new measures to obtain other traffic parameters and new methodologies to use these new data for better signal control are needed. Arterial roads with multiple intersections and coordinate systems can benefit from these spatial domain data as it allows vehicles to move without being stopped.

For a heterogeneous traffic flow, multi-class cell transmission (M-CTM) is used to optimize signal timing control. M-CTM should work well in modeling traffic flow with signal coordination along an arterial where the platoon dispersion effect is significant and has to be accounted for in order to achieve accurate modeling results. Furthermore, queue length estimation was developed to use connected vehicle data without relying on a conventional detector. Lastly, an adaptive signal control based on the queue length estimation and connected vehicle technology was developed and compared with the pre-timed signal in various traffic conditions. The results show that the proposed control logic works well in both the free-flow condition and the congested condition, can decrease total delay, and can prevent queue overflow.

 

Keywords:  Connected Vehicle, Adaptive Signal Control,Queue Estimation, Discrete Wavelet Transform

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Sustainability of Transportation Structures Using Composite Materials to Support Trade and Growth

Shobeir Pirayeh Gar, Stefan Hurlebaus, John B. Mander, Wesley Cummings, Michelle J. Prouty, and Monique H. Head, June, 2014

Corrosion-induced deterioration of steel rebar is one of the main reasons for repair and rehabilitation programs for conventional steel-reinforced concrete bridge decks. According to the National Association of Corrosion Engineers (NACE), of all bridges in the United States, over 50 percent are constructed of conventional steel-reinforced or prestressed concrete, and one in three bridges is considered structurally deficient or functionally obsolete due to corrosion of steel reinforcement. NACE has estimated the annual cost of corrosion-related maintenance of highway bridges in the United States at $8.3 billion.

To overcome corrosion-induced structural issues, researchers have introduced and applied fiber-reinforced polymer (FRP) bars, over the past couple of decades, as a corrosion-resistant candidate for either conventional reinforcing steel or prestressing strands. High strength-to-weight ratio, corrosion resistance, and accelerated construction due to ease of placement of the bars and implementation are the special characteristics that make these bars an appealing alternative for either steel-reinforcing bars or prestressing strands.

This report presents the experimental and analytical investigations of structural performance of a full-scale American Association of State Highway and Transportation Officials (AASHTO) I-girder Type I, reinforced and prestressed with aramid-fiber-reinforced polymer (AFRP) bars, where the bridge girder is composite with a topping deck. The major objectives of this research included evaluating (1) the constructability, (2) the load and deformation capacities under either flexure or shear tests, and (3) the structural performance per AASHTO load and resistance factor design (LRFD) criteria.

The results of this research confirm the adequate strength and deformation capacities of the composite girder, satisfying the AASHTO LRFD criteria. The flexural capacity of the composite girder was about 1582 kNm (1167 kft.), which is 20 percent greater than the maximum factored load, 1326 kNm (978 kft.), per AASHTO LRFD. Under the flexure test, the failure mode of the girder was recognized as the tendon rupture in the bottom flange, where the maximum compressive strain in the topping deck did not reach a failure value equal to −0.003. Such a failure mode was expected because it is not practical to fit too many FRP bars within the bottom flange of the girder to over-reinforce the section and change the failure mode from tendon rupture to concrete crushing in the top fiber of the section.

Keywords: Bridge Girder, Aramid-Fiber-Reinforced Polymer (AFRP), I-Girder, Composite Action, Composite Material

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Effect of Changing Driving Conditions on Driver Behavior Towards Design of a Safe and Efficient Traffic System

Fereydoun Aghazadeh, Laura Hughes Ikuma and Sherif Ishak, December, 2013

This simulation-based study explores the effects of different work zone configurations, varying distances between traffic signs, traffic density and individual differences on drivers’ behavior. Conventional Lane Merge (CLM) and Joint Lane Merge (JLM) were modeled in a driving simulator and thirty participants (seven female and 23 male students) navigated through the two configurations with two levels of traffic density and in three different conditions: a) standard sign distance, b) 25% reduction, and c) 25% increase in the distance between traffic signs in the advance warning zone. Information regarding travel time, speed, braking force and location of merge was collected through the simulator. Self-reported measures of mental demand, physical demand, temporal demand, performance, effort, frustration and total workload were recorded from all participants by using the NASA TLX. The results show that, on average, driving through the JLM took 18.8% longer than the CLM. Moreover, no significant difference in speed was found between the two merge configurations. However, the percent maximum braking force was34% lower in the JLM configuration. The comparison of two merge configurations with respect to the location of changing lanes suggest that overall, the JLM configuration encourages drivers to remain in the closed lane longer. The analysis of self-reported workload ratings shows that participants reported 15.3% lower total workload and 18.8% higher performance when driving through the JLM. Moreover, mental demand, temporal demand, effort and frustration were lower in JLM by 16.4%, 23.4%, 13.7% and 28%, respectively. In terms of self-reported workload, the JLM is more conducive to driving. In conclusion, the JLM outperforms the CLM.

Keywords: Work Zone, Joint Merge Configuration, Driver Behavior

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Game-Theoretic Analysis of Dynamic Traffic Equilibria

Stephen D. Boyles, Christopher Melson, Tarun Rambha, and Jennifer C. Duthie, March 2014

Dynamic traffic assignment has grown steadily in popularity and use since its inception. It has become an important and permanent tool in transportation agencies across the country. However, the exact nature of dynamic traffic equilibrium, including existence and uniqueness results, is not fully known in simulationbased models. Specifically, we discuss the possibilities of unrealistic multiple equilibria that arise out of simplified flow models. We demonstrate this with a simple diverge-merge network and discuss piecewiselinear fundamental diagrams as one possible resolution.

Keywords: Dynamic Traffic Assignment, Multiple Equilibria, Fundamental Diagrams

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Strategic Transportation Finance Clearinghouse

Robert Farley, David Ellis, Allison Weldon, May 2014

Between now and 2030, there will be a significant gap, well in excess of $100 million, between the amount of revenue needed to funded infrastructure projects and the amount of revenue available to fund those projects in Texas. At the same time, there is private capital seeking to invest in infrastructure projects. Despite the need for capital on the part of the public sector and the willingness to supply capital on the part of the private sector, to date, there have been only a limited number of public-private partnership projects. This paper seeks to begin a process to construct an environment in which more projects can be funded with private capital to the benefit of both the public and private sectors.

Keywords: Public-private Partnership

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Use of Directional Median Openings on Urban Roadways

Yi Qi, Xiaoming Chen, Yubian Wang, Guanqi Liu, and Yan Lu, May 2014

Over the past decades, many states and local transportation agencies have installed directional median openings on divided roadways to improve arterial safety and operational performance. A directional opening is normally used to restrict crossing and left-turn movements from minor streets to help avoid potential conflicts. A series of potential benefits may be achieved by installing directional-median openings, including reduced crash rates, increased traffic capacity, and better operational performance. However, the benefits of directional median openings depend largely on proper implementation and on various factors, including geometric, traffic control, environmental conditions, and the type and placement of the downstream U-turn provisions. The goal of this research is to investigate the safety impacts of installing directional openings on median-divided urban roadways. To achieve this goal, the research : 1) synthesized existing related research; 2) compared the safety performance of directional median openings and full median openings, at subject opening locations and downstream U-turn locations; and 3) analyzed the contributing factors to the crashes occurred at the downstream U-turn locations of a directional median opening.

The studies led to a number of findings. Some of the highlighted findings include: 1) Converting a full median opening to directional median opening will reduce the crash frequency at the subject opening location. Although directional median opening might increase the crash frequencies at downstream U-turn locations, the total crashes at subject openings and downstream U-turn locations are still lower than that at full median openings.; 2) The total numbers of crashes at downstream U-turn locations of directional median openings were significantly affected by downstream U-turn volume, downstream left-turn volume, and distance to downstream U-turn opening. Higher downstream U-turn volume and downstream left-turn volume would result in more crashes at downstream U-turn locations. The closer the downstream U-turn location to the subject opening, the more crashes at downstream U-turn location. These findings indicates that, since converting a full median opening to a directional median opening will generate more U-turns at downstream opening of directional opening, the selection of U-turn location is critical for the safety performance of directional openings. Diverted left-turn traffic should not be allowed to make U-turns at closely spaced openings that already have significant U-turns or left-turn volumes.

Keywords: Directional Median Opening, Full Median Opening, Downstream U-turn Location, Poisson Regression Model

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Exploring Sustainable Transportation for Texas Southern University

Gwen Goodwin, Sascha Sabaroche, and Walter Council, May 2014

Texas Southern University is a commuter campus with students, faculty, and staff traveling from the Greater Houston area to the university. Over the past few years, the TSU campus has made marked improvements to move towards a “greener” more sustainable campus with less impervious coverage. Despite this commitment, the campus still has not addressed how the university will decrease its carbon footprint and change the way people arrive at the campus. Adopting a multi-facetted approach to commuting where faculty, staff, and students have the sustainable commuting options: i.e. rideshare, transit, drive, and bicycle, as viable alternatives to get to the university. The literature and practices currently in use show these strategies are already working well at other campuses and could prove success at TSU as well.

Keywords: Campus Commutes, Sustainable Transportation, Sustainable Commuting Options, Alternative Commutes to Universities

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Real Time Freeway Incident Detection

Moggan Motamed and Randy Machemehl, April 2014

The US Department of Transportation (US-DOT) estimates that over half of all congestion events are caused by highway incidents rather than by rush-hour traffic in big cities. Real-time incident detection on freeways is an important part of any modern traffic control center operation because it offers an opportunity to maximize road system performance. An effective incident detection and management operation cannot prevent incidents, however, it can diminish the impacts of non-recurring congestion problems. The main purpose of real-time incident detection is to reduce delay and the number of secondary accidents, and to improve safety and travel information during unusual traffic conditions. The purpose of this project is to evaluate two recently developed automatic incident detection algorithms. The majority of automatic incident detection algorithms are focused on identifying traffic incident patterns but may not adequately investigate possible similarities in patterns observed under incident-free conditions. When traffic demand exceeds road capacity, the traffic speed decreases significantly and the traffic enters a highly unstable regime often referred to as “stop-and-go” conditions. The most challenging part of real-time incident detection is recognition of traffic pattern changes when incidents happen during stop-and-go conditions. This work describes a case study evaluation of two recently evolved incident detection methods using data from the Dallas, TX traffic control center.

Keywords:  Incident Detection, Dynamic Time Warping, Support Vector Machine DTW, SVM

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A Real-time Transit Signal Priority Control system that Considers Stochastic Bus Arrival Times

Xiaosi Zeng, Kevin Balke, Praprut Songchitruksa, and Yunlong Zhang, October 2013

Transit Signal Priority (TSP) is an effective strategy for providing preferential treatment to move transit vehicles through intersections with minimum delay. However, TSP can disrupt traffic on non-priority phases if not properly implemented. To produce a good TSP strategy, advance planning with enough lead time is usually preferred; however, this means added uncertainty about the bus arrival at the stop bar, which has been difficult to be accounted for. In this research, we proposed a stochastic mixed-integer nonlinear model (SMINP) to be used as the core component of a real-time transit signal priority control system. The SMINP was implemented in a simulation evaluation platform. An analysis was performed to compare the proposed control model with the standard check-in/check-out TSP system implemented in the VISSIM Built-in Ring-Barrier Controller (RBC-TSP). The results showed the SMINP produced as much as 30% improvement of bus delay from the RBC-TSP in low to medium volume conditions. In high-volume conditions, the SMINP model automatically recognizes the level of congestion of the intersection and gives less priority to the bus so as to maintain a minimum impact to the traffic on its conflicting phases. In the case of multiple conflicting bus lines, a rolling optimization scheme was developed. A comparison indicated the RBC-TSP systems cannot handle high degree of saturation when there are significant amount of conflicts between bus lines, while the SMINP can automatically give less priority to bus so as to cause much less impact to other traffic.

Keywords: Transit Signal Priority, Mixed-integer Nonlinear Model, Stochastic Optimization, Degree of Saturation, Simulation Evaluation

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Texas Flexible Pavements and Overlays:  Year 1 Report – Test Sections, Data Collection, Analysis, and Data Storage System

Lubinda F. Walubita, Gautam Das, Elida Espinoza, Jeongho Oh, Tom Scullion, Sang Ick Lee, Jose L. Garibay, Soheil Nazarian, and Imad Abdallah, June 2012

This five-year project was initiated to collect materials and pavement performance data on a minimum of 100 highway test sections around the State of Texas, incorporating both flexible pavements and overlays. Besides being used to calibrate and validate mechanistic-empirical (M-E) design models, the data collected will also serve as an ongoing reference data source and/or diagnostic tool for TxDOT engineers and other transportation professionals.

Towards this goal, this interim report provides a documentation of the work completed in Year 1 of the project including the following: 1) literature review; 2) development of data collection and analysis plans, and 3) field test sections. The MS Access Data Storage System, used for storing and accessing the collected data, is also discussed in this interim report.

Keywords: HMA, Flexible Pavements, Overlays, MS Access, Data Storage System, Test Section, M-E Model

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Characterization and Best Use of Recycled Asphalt Shingles in Hot-Mix Asphalt

Fujie Zhou, Hongsheng Li, Sheng Hu, Joe W. Button, and Jon A. Epps, July 2013

Recycled asphalt shingles (RAS) often containing more than 20 percent asphalt binder has become another black gold in the asphalt industry. There are two basic types of RAS scraps in the market: tear-off asphalt shingles (TOAS) and manufacture waste asphalt shingles (MWAS). Both TOAS and MWAS have been used in hot-mix asphalt (HMA) paving in Texas. Since RAS binder is very stiff, lots of concerns have been raised on using RAS in HMA. The researchers conducted a comprehensive investigation on HMA mixes containing RAS, including RAS binder characterization and blending charts for virgin/RAS binders, impact of RAS content on optimum asphalt content (OAC) and engineering properties of RAS mixes, and approaches for improving cracking resistance of RAS mixes. Furthermore, a variety of RAS field test sections were constructed to validate the approaches for improving cracking resistance of RAS mixes. Additionally, this report discusses the environmental and economic benefit of using RAS in HMA. Based on the research performed, it was found that TOAS binders with an average of high temperature grade of 175°C are much stiffer than MWAS binders, which have an average of high temperature grade of 131°C. Impact of MWAS binder on the high and low PG temperatures of virgin binder is different from that of TOAS binders. Thus it is important to consider differentiating MWAS from TOAS when used in asphalt mixes. The use of RAS has no significant influence on dynamic moduli of HMA mixes, but improves their rutting/moisture damage. However, RAS mixes have very poor cracking resistance, compared with the 0 percent RAS mixes with PG64-22 or PG70-22, even though the RAS mixes have higher OAC. Two approaches for improving cracking resistance of RAS mixes were explored in the laboratory. The test results clearly indicated that both using soft binder and increasing design density can improve cracking resistance of RAS mixes. When considering rutting/moisture damage of RAS mixes, using soft binder is superior to increasing design density. Furthermore, a series of field test sections have been constructed around Texas. The observed field performance of the test sections indicated that RAS mixes can be successfully used as surface layer of new construction with strong foundation. It also has been observed that the use of extra virgin asphalt binder (or increasing design density) can effectively improve cracking performance of RAS mixes. Apparently, more work is also needed to investigate the performance of RAS/RAP mixes produced at the warm mix temperatures.

Keywords: Recycled Asphalt Shingle, Hot-Mix Asphalt, Mix Design

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Initial Review of Rapid Moisture Measurement for Roadway Base and Subgrade

Stephen Sebesta, Jeongho Oh, Sang Ick Lee, Marcelo Sanchez, and Ross Taylor, May 2013

This project searched available moisture-measurement technologies using gravimetric, dielectric, electrical conductivity, and suction-based methods, as potential replacements for the nuclear gauge to provide rapid moisture measurement on field construction projects. Such testing is critical for acceptance of field compaction, and could become more critical as states look toward mechanistic-based acceptance. The first phase of this project, presented in this report, carried out test method development, pilot testing, and then initial deployment of the most promising devices. These activities confirmed the utility of existing direct heat and microwave oven tests, revealed promising results with an electrical-impedance based field test, and resulted in draft test procedure development with a portable dielectric-based device and a moisture analyzer. Several procedures evaluated only test the passing No. 4 fraction; reliably predicting the moisture content on the full gradation from the passing No. 4 measurement remains a topic needing further investigation. Future work on this project will deploy the most promising devices on a number of construction projects representing a spectrum of materials, where the devices will be evaluated for bias, precision, and sensitivity. Additionally, this project identified and pilot tested a microwave resonance-based device that may enable rapid field moisture measurement with a high level of testing coverage. Future work on this project will continue development work with applying this device to windrows and processed construction materials.

Keywords: Moisture Content, Moisture Measurement, Water Content, Rapid, Soil Density Gauge, Electrical Density Gauge, Nuclear Gauge, DOT 600, SDG, EDG, Microwave, Direct Heat, Moisture Analyzer

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Katy Freeway:  An Evaluation of a Second-Generation Managed Lanes Project

Ginger Goodin, Robert Benz, Mark Burris, Marcus Brewer, Nick Wood, and Tina Geiselbrecht, May 2014

The Katy Freeway Managed Lanes (KML) represents the first operational, multilane managed facility in Texas and provides an opportunity to benefit from the lessons learned from the project. This study evaluated multiple aspects of KML and the critical areas of project development, design, and operation. One sample finding is that travel time savings are approximately 5 minutes in the morning and 14 minutes in the afternoon in the peak directions, and the travel time advantage over the general-purpose lanes has increased as volumes have grown. Continual monitoring and adjustment of operating aspects of new managed lanes is required post-opening, especially during the ramp-up period in which drivers make travel adjustments to use the facility. The operating partners for the KML have continuously monitored the performance of the lanes since opening and have made adjustments in toll rates, lane configuration at the tolling zones, and access operations at the western terminus. These adjustments are critical to ensuring that the performance standards for the lanes are maintained.

Keywords: Katy Freeway, Managed Lanes, HOV Lanes, HOT Lanes, Express Lanes, Performance Evaluation, Freeway Operations

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Texas-Specific Drive Cycles and Idle Emissions Rates for Using with EPA’s MOVES Model – Final Report

Mohamadreza Farzaneh, Josias Zietsman, Doh-Won Lee, Jeremy Johnson, Nicholas Wood, Tara Ramani, and Chaoyi Gu, May 2014

The U.S. Environmental Protection Agency’s (EPA) newest emissions model, MOtor Vehicle Emission Simulator (MOVES), uses a disaggregate approach that enables the users of the model to create and use local drive schedules (drive cycles) in order to perform an accurate analysis. However, only the national average drive schedules are currently included in the default database of the model. Furthermore, the cold start and idling emissions and activity data of heavy duty diesel trucks (HDDVs) that are included in the MOVES model are based on a very limited number of data sources even though they are very important components of the total on-road mobile source emissions inventory. This report provides local drive cycles for different regions of Texas for different vehicle classes and roadway types as well as cold start and idling emissions rates for heavy-duty diesel trucks. The report also compares estimated emissions from MOVES for a sample of vehicles to real-world in-use emissions measurements. Furthermore, the technical and tactical issues of integrating the results of this study into MOVES for formal emissions analyses purposes are investigated and recommendations provided based on the findings.

Keywords: MOVES, Emissions, Drive Cycles, Drive Schedules, Operating Mode

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Evaluation of Binder Aging and Its Influence in Aging of Hot Mix Asphalt Concrete:  Technical Report

Charles J. Glover, Guanlan Liu, Avery A. Rose, Yunwei Tong, Fan Gu, Meng Ling, Edith Arambula, Cindy Estakhri, and Robert Lytton, April 2014

Warm mix asphalt (WMA) technologies, through reduced mixing and placement temperatures, have reduced fuel consumption, enhanced compaction, increased haul distances and an extended paving season. Issues of concern in WMA are binder oxidation and absorption and their impact on pavement durability. Key future work should combine results from this project with other recent TxDOT projects to develop a comprehensive and fundamentals based mixture design and pavement performance prediction methodology that accounts for climate, traffic loading, pavement structural properties, life-cycle cost analysis, and that is applicable to HMA, WMA, polymer-modified binders, and mixtures that incorporate RAP and RAS. Such an effort would be a major contribution to pavement design and is a realistic goal.

Some other key findings are: 1) absorption is directly related to aggregate void fraction, 2) WMA absorption is somewhat less than HMA absorption, 3) the DGC provides a reliable and relatively easy measure of absorption for an aggregate/binder pair, 4) standard (ASTM) methods for measuring absorption can be problematic, depending on the level of absorption, 5) binders modified using warm mix technologies were found to have similar oxidation kinetics to their base binders, 6) the overlay tester and VEC measurements were successfully used to characterize mixture fatigue, 7) mixture fatigue resistance declines with binder oxidation, a result that is omitted entirely from typical pavement design guides (e.g., the MEPDG), and 8) during the first summer of its service life, oxidative aging, curing, and absorption have a significant beneficial effect on the performance of warm mixes.

Keywords: Asphalt Oxidation Kinetics, DSR Function, Carbonyl Area, Density Gradient Column, Warm Mix Asphalt, Mixture Stiffness Gradient, Asphalt Absorption, Dynamic Mechanical Analyzer, Asphalt Specification

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Research to Develop an ITS Strategic Plan for Texas

Ed Seymour, Beverly Kuhn, Kevin Balke, Nadeem Chaudhary, Debbie Jasek, Rajat Rajbhandari, Tony Voigt, Kristine Miller, Tina Geiselbrecht, and Steven Venglar, April 2014

TxDOT’s mission is to provide safe and reliable transportation solutions for the citizens of Texas. Intelligent transportation systems (ITS) can play a pivotal role in meeting that mission. TxDOT can take advantage of advanced and emerging technologies to enhance safety and promote reliability by ensuring that travelers see the transportation network as a seamless system that helps get them to their destinations and deliver goods and services to the citizens of Texas with as little disruption as possible. ITS is a critical component of the transportation infrastructure that helps ensure the system operates in the most efficient way possible every day, every night, and during all types of situations and weather conditions. TxDOT has four primary goals related to meeting its mission. These goals are: maintain a safe system, address congestion, connect Texas communities, and become a best-in-class state agency. The agency cannot hope to successfully meet these goals without ITS in its arsenal of strategies to advance transportation across the state. This report documents the research that was undertaken to develop the ITS Strategic Plan for Texas. This research included an assessment of current U.S. trends in ITS and related initiatives, interviews with ITS stakeholders across Texas to determine needs, and a peer state review. The plan provides a framework to guide the development and deployment of an integrated statewide program for Intelligent Transportation Systems. The Texas Transportation Commission, TxDOT, as well as the broad community of ITS providers, stakeholders, and agency partners, will use this plan to promote the development, deployment, and use of ITS statewide. If this plan is to succeed, it needs the cooperation of all affected groups involved in ITS and transportation planning, design, funding, and implementation in the state.

Keywords: ITS Initiative, Stakeholder, 511 Deployment, Performance Monitoring, Aggregation Level, Data Filtering, Data Imputation, Data Provision, Map Matching, Accuracy Check, Light Flow, Connected Vehicle Initiative

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Laboratory Evaluation of Asphalt Binder Rutting, Fracture, and Adhesion Tests

Fujie Zhou, Hongsheng Li, Peiru Chen and Tom Scullion, April 2014

The current performance grading (PG) specification for asphalt binders was developed based on the Strategic Highway Research Program (SHRP) and is based primarily on the study of unmodified asphalt binders. Over the years, experience has proven that the PG grading system, while good for ensuring overall quality, fails in some cases to predict rutting and cracking performance, particularly as it applies to softer but highly modified binders. Therefore, it is necessary to improve current asphalt binder performance parameters and associated specification limits, especially for modified binders.

This report documents the laboratory evaluation of several new tests for rutting, fatigue, and adhesion property of asphalt binders, including the multiple stress creep and recovery (MSCR) test, linear amplitude sweep (LAS) test, double edged notched tension (DENT) test, elastic recovery test, pull-off test, pneumatic adhesion tensile testing instrument (PATTI), dynamic mechanical analyzer (DMA) test, and surface energy test. It was found that the MSCR test and associated specification works better than the current G*/sin -based PG specification, especially for those highly modified asphalt binders (such as PG64 34). MSCR round robin results among five laboratories clearly indicated that both Jnr0.1 and Jnr3.2 results are very repeatable and reproducible, but both Jnrdiff and R0.1 have pretty high variability. Since Jnrdiff is one of the parameters for grading asphalt binder, caution should be exercised when applying the MSCR specification. The R3.2 results are acceptable in terms of repeatability and reproducibility. Based on the laboratory test results, users should exercise some caution when grading the slightly modified asphalt binders (such as PG64-28) using the MSCR test and associated specification. This study further confirms the poor relationship between the parameter G*sinδ and the binder fatigue resistance. Neither the MSCR nor the elastic recovery test shows good correlation with the asphalt mix OT cracking test. Both the LAST and the DENT tests provide similar ranking to that of asphalt mix OT cracking test. The DSR-based LAS test is recommended for asphalt binder fracture test, since the DSR has been widely used in the last 20 years. Additionally, only the PATTI test is a promising test for evaluating adhesive properties of asphalt binders. All three other tests (the pull-off test, DMA, and surface energy test) were not successful in this study for evaluating asphalt binder adhesion property.

Obviously, these laboratory findings need further field validation. Additionally, one needs always to keep in mind that the binder alone does not determine field performance of asphalt mixes. Mix characteristics as well as the pavement structure itself, traffic, and the environment within which it is located have a significant role in determining pavement performance.

Keywords: Asphalt Binder, Multiple Stress Creep Recovery Test, Fracture Test, Adhesion Test

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Compendium of Student Papers: 2013 Undergraduate Transportation Scholars Program

Daniel Bartilson, Adrian Contreras, Kevin Mackan, Mark Membreño and Parker C. Moore, Authors, and H. Gene Hawkins, Editor, November 2013

This report is a compilation of research papers written by students participating in the 2013 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 23nd year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics: 1)Validation of Computer Vision for Structural Vibration Studies; 2) Evaluating Driver Response to Prototype Traffic Control Devices at Access Points; 3) Evaluation of Apparent Capacities through Freeway Lane Closures; 4) Operational Effects of Chevrons on Horizontal Curves Using Speed and Energy Differentials and Speed Profiles; and 5) Preliminary Development of a Trip Generation Manual for Texas.

Keywords: Structural Vibration, Traffic Signal Structure, Access Management, Traffic Control Devices, Work Zone Traffic Control, Highway Capacity, Traffic Signs, Roadway Geometry, Trip Generation

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An Examination of Severe Environmental Justice Zones in Houston, TX

Gwen Goodwin, Jamaal Schoby and Walter Council, April 2014

Declining federal subsidies are limiting transportation capacity at the regional and local levels. At the same time, federally funded agencies must comply with Executive Order (EO) 12898, which augments Title VI of the Civil Rights Act of 1964. The EO states that agencies are to identify burdens and benefits to vulnerable populations. Prior to the 2010, demographic and socioeconomic data collected from the decennial census, the American Community Survey (ACS) and the United States Department of Health and Human Services were used to classify environmental justice zones. In the 2010 decennial census, the U.S. Census Bureau eliminated the long-form, which reduced the data available to perform adequate environmental justice analyses. Currently, metropolitan planning organizations (MPOs) use the ACS which provides limited data. MPOs must now develop innovative strategies to determine environmental justice zones. In previous work, a methodology for identifying EJZs in the Houston TMA was created for the MPO. This methodology analyzed the level of transportation investment in severe census tracts. The methodology included a three-tier process. First, the EJZs and non-EJZs were identified based on the distribution of variables throughout the census tracts. Of the 1,066 tracts within the Houston transportation management area (TMA), there was usable data for 1,062 tracts. About 356 (34%) were classified as EJ Zones. Among EJ tracts, 209 (20%) were low EJ, 107 (10%) were medium EJ, 32 (3%) were high EJ, and 8 (1%) were extreme EJ tracts. For purposes of this study, only these eight extreme EJ zones are discussed in more detail. The second tier analysis developed community profiles for these extreme EJZs. In the third tier, transportation mobility accessibility options were described for the extreme EJZs, including an automobile versus public transit comparison. The study found that one of the EJ areas had the best travel times and good access to transit and light rail. This was primarily due to its close proximity to the CBD. Study areas located the farthest from the CBD reported higher car ownership.

Keywords: Urban Transportation, Environmental Justice Zones

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Left-Turn Lanes at Unsignalized Median Openings

Yi Qi, Xiaoming Chen, Yubian Wang, and Yan Lu, March 2014

Due to the frequent presence of median openings in urban arterial settings, the requirements for the deceleration and storage of turning vehicles (e.g. AASHTO Green Book) often exceed the available length between two adjacent openings which leaves traffic engineers having to decide whether left-turn lanes, shorter than the standards, can be used or not. The goal of this research is to investigate the minimum required length for the left-turn lanes at the unsignalized median openings, and study the safety and operational impacts of such left-turn lanes with substandard lengths. To achieve this goal, researchers will: 1) synthesize existing related research; 2) develop models for storage lengths at unsignalized median openings; 3) develop models for estimating the delays caused by substandard deceleration lengths and the resulting excessive deceleration on main travel lanes; and 4) analyze safety impacts of substandard median left-turn lanes.

The results of this study lead to following key findings: 1) at the operational impacts perspective- if a substandard length left-turn lane can accommodate the necessary storage length and the deceleration length assuming a 20mph speed differential, it will not affect the operational performance of median openings significantly and the delays caused by using substandard length left-turn lane are significantly less than the delays associated with the absence of dedicated left-turn lanes; 2) at the safety impacts perspective- substandard length left-turn lanes will affect the safety performance of median openings. However, when it is impractical to provide the Greenbook required length, use of substandard length left-turn lanes may still be an option because of operational benefits comparing the no dedicated left-turn lane option; and 3) based on traffic simulation study- the required storage length is less than that estimated by the AASHTO “two-minute arrival” rule-of-thumb method. The minimum required storage length can be estimated with the regression model developed in this research.

Keywords:  Short Left-Turn Lane, Storage Length, Operational Performance, Traffic Safety, Unsignalized Median Openings, Substandard-length Median Turn Lane

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State and Regional Tools for Coordinating Housing and Transportation

Akul Nishawala, Kate Lowe and Marla Nelson, January 2014

Federal, state, and local governments spend billions on transportation infrastructure and affordable housing subsidies, but rarely with complete coordination. States and regional entities are pivotal in shaping transportation and housing systems. State agencies not only spend state-generated revenue but also frequently determine how federal resources are allocated. The largest federal subsidy for affordable, rental housing is the low-income housing tax credit program, but states largely determine the allocation of these credits. With increasing attention on the need to combine affordable housing with mobility options, this report examines which states have incorporated transit proximity into their allocation of low-income housing tax credits. In addition, the report also reviews to what extent low-income residential patterns are included in federally required, regional transportation planning. We find that most states address transportation in their allocation of low-income housing tax credits, with the most common transportation criterion being proximity to transit (e.g., whether a development was .25 or .5 miles from transit). Across metropolitan areas, our scan of regional plan documents revealed inconsistent consideration of the residential locations of low-income households. In both policy areas, we thus observe some attention to the relationship between housing location (for low-income households) and transportation systems. The steps toward integration are still new, without documented efficacy, and even with initial progress and attention across spheres, integration challenges may remain.

Keywords: Affordable Housing, Low-income Households

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Sustainability of Bridge Foundations Using Electrical Resistivity Imaging and Induced Polarization to Support Transportation Safety

Stefan Hurlebaus, Jean-Louis Briaud, and Stacey Tucker, January 2014

As of September 2007, there were 67,240 U.S. bridges in the National Bridge Inventory classified as having unknown foundations (FHWA 2008). The bridges spanning rivers are of critical importance due to the risks of potential scour. In fact, it is estimated that 60 percent of all bridge collapses are due to scour (Parola et al. 1997). Not only are these failures costly, they can be deadly for the traveling public. On April 5, 1987, 10 people were killed in New York when a pier collapsed on the Schoharie Creek Bridge causing two spans of the deck to fall into the creek. Several other fatal collapses have occurred since the Schoharie Creek Bridge failure. Detecting scour is only part of the assessment that must take place to determine risk of failure and knowing the foundation depth is a critical component of the assessment.

This research explored the feasibility and effectiveness of induced polarization (IP) and electrical resistivity imaging (ERI), near surface geophysical methods, for determining the depth of unknown foundations. With budget cuts and deteriorating infrastructure, there is a need to seek alternative solutions for nondestructive structural integrity testing that are more robust to limit bridge failures that hinder transportation safety. The existing methods for unknown bridge foundations in the literature are often hindered by the type of foundation or require the use of a borehole, making them very costly. As a result, only a few states are working to identify the depth of unknown bridge foundations around them. In order to solve this national problem, a new and effective method needs to be investigated with full scale bridge testing and disseminated nationwide. In this work, an experimental study was conducted at a National Geotechnical Experimentation Site (NGES) to identify key parameters for the testing design and setup in order to obtain optimal surveys of bridge foundations. The conclusions of the NGES investigations were used to plan the field surveys on four bridges with known foundations. The outcomes of the four bridges showed that IP and ERI can be used in concert with one another to estimate the type and depth of bridge foundations. The results of the field surveys were used to create a probability of non-exceedance curve for future predictions of unknown bridge foundations using the methods described in this research. Finally, the probability of exceedance curve was used to validate the method with testing on a foundation unknown at the time of testing, and the use of IP and ERI were extended to other subsurface infrastructure when a gas line was imaged.

Keywords: Unknown Bridge Foundations, Scour, Electrical Resistivity, Induced Polarization, Probability of Exceedance

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Empirical Measurement of Travelers’ Value of Reliability

Mark Burris and Santosh Rao Danda, March 2014

Time and reliability are two fundamental factors influencing travel behavior and demand. The concept of the value of time (VOT) has been extensively studied, and estimates of VOT have been obtained from surveys and empirical data. On the other hand, although the importance of value of reliability (VOR) is appreciated, research related to VOR is still in its early stages. The VOR has been estimated using surveys but has almost never been estimated using empirical data.

This research used empirical data to take an initial step toward understanding the importance of travel time reliability. Katy Freeway travelers face a daily choice between reliable tolled lanes and less reliable but untolled lanes. An extensive dataset of Katy Freeway travel was used to examine the influence of time, reliability, and toll on lane-choice behavior. Lane choice was estimated using multinomial logit models. Basic models, including only travel time and toll, yielded reasonable results. Models included VOTs of $2.60/hour, $8.63/hour, and $10.71/hour for off-peak, shoulder, and peak-period travelers, respectively.

However, adding a managed-lane (ML) alternative specific coefficient to these models resulted in positive coefficients for the toll variable and negative VOTs. Similarly, adding reliability to the models resulted in counter-intuitive results. Researchers concluded that additional research on how travelers perceive the reliability and time savings on MLs is needed because modeling real-world choices of MLs using the standard definitions of reliability and time savings led to counter-intuitive results.

Keywords: Travel Time Reliability, Value of Time, Value of Travel Time Reliability, Travel Behavior, Lane Choice Behavior

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Automated Vehicles: Policy Implications Scoping Study

Jason Wagner, Trey Baker, Ginger Goodin and John Maddox, January 2014

Automated vehicles are an emerging technology with the potential to greatly change and disrupt the American transportation system, but may also have significant benefits. This study sought to understand how automated vehicles will change the transportation system, identify implications on state and local transportation providers, determine future research needs, and understand emerging policy issues.

To accomplish these ends, the research team performed an in-depth literature review. Following this review, the research team interviewed expert personnel from automated vehicle manufacturers, suppliers, and developers; and state and local transportation agency representatives. These interviews informed the research process and provided insight into the future needs of transportation providers in the face of automated vehicles.

Keywords:  Automated Vehicles, Policy, Transportation, Economics, Implications

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Fatigue Resistance of Asphalt Mixtures Affected by Water Vapor Movement

Yunwei Tong, December 2013

This dissertation has two key objectives: the first objective is to develop a method of predicting and quantifying the amount of water that can enter into a pavement system by vapor transport; the second objective is to identify to which extent the fatigue crack growth of pavement would result from such moisture accumulation. To fulfill these two objectives, a diffusion model was first established to illustrate the wetting process of the surface asphalt layer due to the vapor migration from subgrade soil into the upper layer. Secondly, in order to quantify the degree of moisture damage induced by water vapor diffusion, fine aggregate mixture specimens were fabricated and conditioned at different levels of relative humidity in closed vacuum desiccators that allows little temperature fluctuation. Moreover, the moisture conditioned specimens were tested using a newly developed repeated direct tension test method to evaluate the fatigue crack growth. The RDT test greatly reduced the stress state complexity within the specimens by evenly distributing stress over the cross section area of the cylindrical specimen. Compared to the previous torsional test, the newly proposed test protocol was more efficient in characterizing the moisture susceptibility of the asphalt mixture. A major finding in this dissertation is that the higher level of RH in as asphalt surface layer will induce significantly higher crack growth rates.

Keywords: Water Vapor Diffusion, Fine Aggregate Mixture, Pseudo Strain, Dissipated Pseudo Strain Energy, Surface Energy

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2012 Household Travel Survey Symposium: Conference Summary and Final Report

Stacey Bricka, Ben Ettelman, and Chris Simek, December 2013

The SWUTC Travel Survey Symposium was held in Dallas on November 8 and 9. More than 70 travel survey professionals attended this event from across the United States, from Florida to Alaska, with one attendee from the City of Calgary (Canada), representing an almost equal mix of agency, consultant, and academic researchers. The symposium started with a poster session, featuring research from 22 related efforts. An opening session followed that included a Texas welcome from Mr. Michael Morris, Executive Director of NCTCOG and a key note speech from Dr. Kermit Wies of the Chicago Metropolitan Agency for Planning. Attendees were encouraged to think outside the box and consider all users of travel survey data as their customers.

The symposium was divided into two parts. The discussion groups on Thursday focused on identifying lessons learned and opportunities to advance methods and sampling approaches, as well as considering all uses of the survey data. The day ended with attendees presenting their versions of the “travel survey of the future”—incorporating new technologies, known and on the horizon. Friday, the focus of the symposium discussion turned to identifying what can be implemented now and establishing a research agenda to move us toward the newly identified survey designs.

Keywords: Travel Surveys, Survey Methods, Emerging Data Collection Technologies

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A Multivariate Analysis of Freeway Speed and Headway Data

Yajie Zou, December 2013

The knowledge of speed and headway distributions is essential in microscopic traffic flow studies because speed and headway are both fundamental microscopic characteristics of traffic flow. For microscopic simulation models, one key process is the generation of entry vehicle speeds and vehicle arrival times. It is helpful to find desirable mathematical distributions to model individual speed and headway values, because the individual vehicle speed and arrival time in microscopic simulations are usually generated based on some form of mathematical models. Traditionally, distributions for speed and headway are investigated separately and independent of each other. However, this traditional approach ignores the possible dependence between speed and headway. To address this issue, the research presents a methodology to construct bivariate distributions to describe the characteristics of speed and headway. Based on the investigation of freeway speed and headway data measured from the loop detector data on IH-35 in Austin, it is shown that there exists a weak dependence between speed and headway.

The research first proposes skew-t mixture models to capture the heterogeneity in speed distribution. Finite mixture of skew-t distributions can significantly improve the goodness of fit of speed data. To develop a bivariate distribution to capture the dependence and describe the characteristics of speed and headway, this study proposes a Farlie-Gumbel Morgenstern (FGM) approach to construct a bivariate distribution to simultaneously describe the characteristics of speed and headway. The bivariate model can provide a satisfactory fit to the multimodal speed and headway distribution. Overall, the proposed methodologies in this research can be used to generate more accurate vehicle speeds and vehicle arrival times by considering their dependence on each other when developing microscopic traffic simulation models.

Keywords:  Speed, Headway Correlation, Heterogeneity

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Game Theory and Traffic Assignment

Tarun Rambha and Stephen D. Boyles, September 2013

Traffic assignment is used to determine the number of users on roadway links in a network. While this problem has been widely studied in transportation literature, its use of the concept of equilibrium has attracted considerable interest in the field of game theory. The approaches used in both transportation and game theory disciplines are explored, and the similarities and dissimilarities between the m are studied. In particular, treatment of multiple equilibrium solutions using equilibrium refinements and learning algorithms which convergence to equilibria under incomplete information and/or bounded rationality of players are discussed in detail.

Keywords: Congestion Games, Traffic Assignment, Learning in Games, Equilibrium Refinements

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Developing the Sediment and Erosion Control Laboratory to Become a Hands-on Training and Education Center

Ming-Han Li, Pengzhi Li, Jett McFalls, Beverly Storey and Galen Newman, November 2013

The Sedimentation and Erosion Control (SEC) Laboratory has an established reputation as a renowned soil erosion research facility in the United States since its inception in 1990. During the past two decades, the lab has expanded its original performance evaluation task to cutting-edge stormwater research, as well as professional training development. The researchers affiliated with the SEC Lab have also developed numerous training courses.

In the market of continuing education industry, a popular business is to provide courses on soil erosion and Low Impact Development (LID) subjects. As the growing demand on these topics, there are more and more continuing education programs starting to set up training courses on this topic. However, those programs rarely can provide hands-on training. Therefore, the opportunity arises where Texas A&M Transportation Institute can depend on the SEC Lab for hands-on exercises to be integrated in professional training, continuing education and high-impact learning experiences for current TAMU students, regional municipalities, and other professionals in the design and construction industries.

Considering SEC Lab has never developed a master plan and the demand of continuing education, the research proposed a master plan for the lab and developed a pilot LID course. Tasked conducted include: cases review, SWOT (strength, weakness, opportunity and challenge) analysis, course module development, conceptual plan design, model build, propagation, and final master plan.

Keywords:  Low Impact Development, Soil Erosion, Stormwater Management, Continuing Education

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Decision-Support Framework for Quantifying the Most Economical Incentive/Disincentive Dollar Amounts for Critical Highway Pavement Rehabilitation Projects

Kunhee Choi, Eun Sug Park, and Junseo Bae, November 2013

One innovative way of reducing construction duration is to reward contractors with an early completion incentive bonus and levy fines for delays. Although use of Incentive/Disincentive (I/D) is increasingly common, State Transportation Agencies (STAs) often struggle to select the most appropriate I/D rates due largely to the lack of the proper analytical methods. There is an immediate need to develop a holistic framework that is more general and applicable to a variety of transportation projects for the determination of optimal I/D rates.

The main objectives of this study were to create a new decision-support analytical framework of optimal I/D and test whether it can reasonably and realistically determine and justify the most economical I/D dollar amounts. This study blends existing schedule and traffic simulation techniques with a stochastic analysis by accounting for the integration of project schedule, Contractor’s Additional Cost (CAC) of acceleration, and total savings to motorists and to the agency. STAs can arrive at an optimal I/D rate by employing a seven-stage methodology proposed in this study. These steps include two adjustment algorithms that are factored on the concepts of level-of-service and net present value. The study results revealed a strong tradeoff effect between schedule and cost, suggesting that CAC growth rate can be analyzed by how the CAC interacts with the agency’s specified schedule goal. The robustness of the proposed seven-stage methodology was validated with two case studies performed on real-world construction projects.

This research work provides research communities and industry practitioners with the first holistic view to determine the most economical and realistic I/D dollar amounts for a given project—an optimal value that allows the agency to stay within budget while at the same time effectively motivating contractors to use their ingenuity to complete the projects earlier. It can help agency engineers and decision makers make better-informed decisions and allocate more realistic incentives, which will result in more favorable cost-benefit ratios and better use of public funds. It will significantly reduce the agency’s expenses in the time and effort required for determining I/D rates.

Keywords:  Highway Rehabilitation, Innovative Contracting, Decision-Support Model, Incentive/Disincentive, Contractor’s Additional Cost of Acceleration, Road User Cost, Level-of-Service, Net Present Value

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Examining Decision-making Surrounding the Use of Managed Lanes by Katy Freeway Travelers: A Prospect Theory Approach

Chao Huang, December 2013

This study examined if PT is superior to EUT when predicting and understanding travelers’ behavior in the case of MLs by embedding PT proposed value function and probability weighting functions in the utility estimation. From both EUT and PT approaches, this study used survey data from 2012 to predict the mode choices that include MLs and toll-free alternatives, and provided estimates of the value that travelers are willing to pay for travel time savings on MLs. The responses from the survey were examined using advanced discrete choice models. Significant and interesting general findings resemble those in previous studies that use PT, including the fact that individuals weight probabilities. Two survey design methodologies, Db-efficient and adaptive random, were tested in this survey. Estimates from the EUT and PT approaches, as well as from previous studies on Katy Freeway travelers, are compared. The results of this study indicate that Katy Freeway travelers are more risk averse when in a situation of being late for work than they are with potential savings in travel time, and they, on average, demonstrate a sense of optimism when the chances of facing a longer travel time are high.

PT based models, particularly the model embedding with probability weighting, outperforms EUT based models in terms of the predicative power. On average, models with probability weighting resulted in more than 65 percent of all mode choices correctly predicted, while conventional EUT models predict about 35 percent of choices correctly among four alternatives. Compared to previously available route choice studies, the relatively low willingness to pay (WTP) measures ($8 to $14/hour) calculated in this study from the PT models may deserve further investigation. Empirical findings from this study would help the policy makers set up appropriate project goals and toll rates to meet the increasing traffic demand of Katy Freeway travelers.

Keywords: Prospect Theory, Expected Utility Theory, Route Choice Decision

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Public-Private Partnerships in Transportation Infrastructure: Survey of Experiences and Perceptions

Sergio E. Martinez, Andrea Hall, and C. Michael Walton, September 2013

The use of public-private partnerships (PPPs) for transportation infrastructure delivery has increased in the U.S. However, concerns about and opposition to these agreements exist due to a variety of factors. This paper explores the perceptions that a variety of PPP stakeholders have about PPP usage to deliver transportation infrastructure in the U.S., including stakeholders from fields at times overlooked in PPP literature but that are key to these transactions, such as professionals in legal, banking and finance, and concessionaire organizations. The paper reports the results of a survey taken by 101 professionals, with responses classified based on different aspects of the respondents’ backgrounds. Results indicate that stakeholders’ perceptions about benefits, barriers, and valuation of PPPs vary—at times greatly—depending upon the respondent’s work type, location, and especially whether they had previous experience with PPPs. While this is not surprising, in some cases, such variations in perceptions were unexpected in both type and magnitude. It is understandable that some misperceptions still exist among PPP stakeholders due to various reasons, yet some responses showed deep misunderstandings, fears, or unrealistic expectations about PPPs. The fact that respondents were targeted because of their assumed familiarity with these transactions is worrisome and it indicates the need to educate decision-makers, staff, and the general public about what PPPs really are, why they are needed, and what they can and cannot do.

Keywords: Public-Private Partnerships, PPPs, Transportation, Infrastructure, Survey

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Transportation Revenue Impacts from a Changing Light-Duty Vehicle Fleet

Andrea Hall, C. Michael Walton, and Peter J. Jin, September 2013

Advanced fuel economies in both traditional internal combustion engine vehicles (ICEs) and electric vehicles (EVs) have a strong influence on transportation revenue by reducing fuel consumption per vehicle and ultimately drawing down the amount of fuel tax revenue received. It is expected that more ICE vehicles with advanced fuel economies and EVs, especially gasoline hybrid EVs, will enter the roadway in coming years, and fuel tax revenues and the Highway Trust Fund will increasingly become more affected. This study estimates the impact that increased sales of advanced ICEs and EVs will have on future fuel tax revenues by drawing on industry estimates of future EV and ICE market shares and anticipates future fleet mix and fuel economy for both vehicle technologies. An estimation process overview is provided and assumptions are described.

Fuel tax revenue amounts that would be expected from future light vehicle fleets with increased shares of EVs are compared to equivalently sized fleets composed of all ICEs, and future fleet mixes are estimated. Results show that as more EVs enter the light vehicle fleet, greater revenue losses are expected, and total losses from years 2011 through 2050 depend on fleet composition and fuel economy of both vehicle types. It is found that the amount of fuel taxes paid by ICE drivers each year remain greater than fuel taxes paid by EV drivers even with advances in the average ICE vehicle fuel economy. Finally, a review of alternative revenue generation methods that states are employing to cover fuel tax revenue gaps is given.

Keywords: Electric Vehicles, Fuel Tax, Finance, Revenues, Transportation Policy

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A Transportation Corridor Analysis Toolkit

Dan P. K. Seedah, Rydell D. Walthall, Garrett Fullerton, Travis D. Owens, Robert Harrison, October 2013

The Moving Ahead for Progress in the 21st Century Act includes a number of provisions advocating improving the condition and performance of the national freight network through targeted investments and policies by the Department of Transportation and state agencies. Critical to this network are freight corridors which serve as major trade gateways connecting multiple cities and regions. However, transportation planners and policy makers are limited by the number of tools available to assess the performance and condition of these corridors. Most current tools and models require data which is either unavailable, outdated or insufficient for analysis. To address this need, a truck-rail intermodal toolkit was developed for multimodal corridor analysis and enables planners and other stakeholders examine freight movement along corridors based on mode and route characteristics. The toolkit includes techniques to acquire data for simulating line-haul movements, and models to evaluate multiple freight movement scenarios along corridors. Example analyses examining truck and rail movements along 5 mode-competitive corridors are presented in addition to a case study of the Gulf Coast Megaregion. The methodology described herein can be used in other multistate corridors and serve as an initial assessment of the condition and performance of the national freight network.

Keywords: Freight Corridors, Megaregions, Rail, Truck, Fuel Efficiency, Freight Operating Costs

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A Comprehensive Characterization of Asphalt Mixtures in Compression

Yuqing Zhang, Rong Luo, and Robert L. Lytton, August 2013

Permanent deformation (i.e., rutting) is one of the major distresses in asphalt pavements, and it consists of irrecoverable deformation due to viscoplastic flow and viscofracture fatigue damage. The mechanisms of rutting have not been well addressed due to the complexities of asphalt mixture including (a) distinctions between compression, extension, and tension; (b) rate and temperature dependence; (c) dilative volumetric change; (d) frictional material with cohesion; (e) inherent anisotropy due to preferential aggregates’ orientation; (f) crack-induced anisotropy due to crack growth; (g) strain hardening during viscoplastic accumulation; and (h) strain softening during viscofracture evolution.

In this project, all of the aforementioned fundamentals of asphalt mixtures were simultaneously characterized by a comprehensive viscoplastic-fracture mechanistic model, which was incorporated with (a) a modified effective stress to consider the inherent anisotropy and the crack-induced anisotropy due to viscofracture cracking in compression; (b) a smooth and convex Generalized Drucker-Prager (GD-P) yield surface; (c) a non-associated viscoplastic flow rule; (d) a rate- and temperature-dependent strain hardening rule; and (e) a viscofracture evolution that was modeled by an anisotropic damage density-based pseudo J-integral Paris’ law. The model parameters were related to fundamental material properties that were measurable and understandable for civil engineers. A systemic testing protocol including five individual test methods were proposed to determine the model parameters and material properties. The test protocol was demonstrated to be efficient, as one asphalt mixture could be completely characterized within 1 day. The GD-P yield surface model was validated by octahedral shear strength tests at different normal and confining stresses. The GD-P model was able to characterize the full range of the internal friction angles from 0 to 90 degrees. In contrast, the widely used Extended Drucker-Prager (ED-P) model can only be used for a material that has an internal friction angle less than 22 degrees due to the convexity criterion of the yield surface.

Keywords:  Asphalt Mixtures, Rutting, Constitutive Modeling, Compression, Anisotropy, Viscoplasticity, Viscofracture

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Equity Evaluation of Sustainable Mileage Based User Fee Scenarios

Mark Burris, Sunghoon Lee, Tina Geiselbrecht and Trey Baker, October 2013

The Texas state gas tax has been 20 cents per gallon since 1991, and the federal gas tax has been 18.4 cents per gallon since 1993. The gas tax is not only stagnant, but depreciating in value due to inflation.  This is forcing some transportation providers to increase their focus on spending for a more sustainable transportation system, thus shifting how tax revenues are spent. One proposed alternative to the gas tax is the creation of a mileage-based user fee (MBUF), which would then shift how revenues are collected. This research examined potential equity impacts of these shifts in the collection and disbursement of transportation funds.

This research used 2009 National Household Travel Survey (NHTS) Texas data along with detailed spending estimates from the Texas Department of Transportation to consider the equity impacts surrounding three MBUF and spending scenarios. NHTS data were weighted to reflect results representative of Texas vehicle-owning households. Each scenario was run both statically and dynamically under the assumption that the MBUF would replace the state gas tax. Results indicate that the impact of the MBUF on geographic equity can be different depending on allocation of transportation funding. However, the MBUF was essentially as equally vertically equitable as the current state gas tax.

Keywords: Mileage-Based User Fee, Equity, Tax Revenue

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Balanced RAP/RAS Mix Design and Performance Evaluation System for Project-Specific Service Conditions

Fujie Zhou, Seng Hu, and Tom Scullion, Texas A&M University, June 2013, 80 pp.

The use of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) can significantly reduce the increasing cost of hot-mix asphalt paving, conserve energy, and protect the environment. However, the premature cracking problem has been a serious concern. This report presents the latest work on RAP/RAS mix design and performance analysis including field performance of a variety of RAP/RAS test sections around Texas, and the proposed RAP/RAS mix design and performance evaluation system for project-specific service conditions.

RAP/RAS mixes can have better or similar performance than virgin mixes if they are well designed with balancing both rutting/moisture damage and cracking requirements. Cracking performance of RAP/RAS mixes is influenced by many factors, such as traffic, climate, existing pavement conditions for asphalt overlays, and pavement structure and layer thickness. It is obvious that a single cracking requirement does not apply to all asphalt overlay applications. Instead, a project-specific service conditions based mix design system should be developed. Based on the relationship between Overlay Test (OT) cycles and fracture properties (A and n) established under this study, a balanced RAP/RAS mix design and performance evaluation system for project-specific service conditions is proposed, and it includes a balanced mix design procedure and a performance evaluation system in which the Hamburg wheel tracking test and associated criteria are used to control rutting/moisture damage and the OT, and the required OT cycles determined from S-TxACOL cracking prediction with consideration of climate, traffic, pavement structure and existing pavement conditions. Additionally, the impacts of soft binder on engineering properties of RAP/RAS mixes in terms of dynamic modulus, HWTT rut depth, and OT cycles are investigated. The test results clearly indicated that the use of soft and modified asphalt binder (i.e., PG xx-28, PG xx-34) can effectively improve cracking resistance of RAP/RAS mixes without sacrificing much rutting/moisture damage resistance. Dynamic modulus is not a good indicator as cracking resistance of RAP/RAS mixes. Researchers highly recommend that the proposed RAP/RAS mix design and performance evaluation system for project-specific service conditions be implemented statewide.

Keywords: RAP, RAS Mix Design, Overlay Test, Rutting, Cracking

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Transportation Security Institute:  Recruiting Next Generation Professionals

Khosro Godazi and Alexandra Miller, Texas Southern University, August 2013, 29 pp.

The Center for Transportation Training and Research (CTTR), as part of Texas Southern University (TSU), served as host for the 2013 Transportation Security Institute (TSI) in Houston and surrounding area. The 2013 Houston TSI focuses on the mission and objectives of transportation security professionals and introduces a pre-selected group of high school students to the various career opportunities within the profession.

TSI provides a curriculum framework that exposes high school students to the transportation security industry via hands-on technical activities, field trips to transportation facilities, lectures by transportation professionals, and on-site seminars. Furthermore, the primary goal of TSI is to introduce exemplary secondary school students to various career opportunities in transportation security. Secondly, industry professionals will reinforce the importance of mathematics, science, and technology skills in the twenty-first century. Lastly, students will observe how public/private partnerships work to strengthen the link between today’s students and future transportation security professionals.

Keywords: Transportation Security, Transportation Modes, Entrepreneurship, Geographic Information System, STEM-Related Careers

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Investigation of Improvements to Truck Volume Assignments and Public Transportation Benefits Methodologies in TTI’s Urban Mobility Report

William L. Eisele, David L. Schrank, Dong Hun (Don) Kang, Steven E. Polzin and Xuehao Chu, Texas A&M University, August 2013, 65 pp.

The Texas A&M Transportation Institute’s (TTI’s) often-cited Urban Mobility Report (UMR) provides transportation decision-makers with urban-area congestion statistics and trends. Data and their availability have continued to evolve rapidly over the years that this report has been produced, and TTI researchers have updated the UMR methodology as new data sources and information become available.

The objectives of this project were to (a) investigate the UMR methodology assumptions related to the daily volume distributions for trucks and possible methodology improvements, and (b) investigate the UMR methodology related to the benefits of transit ridership and transit delay reduction calculations and possible methodology improvements.

To satisfy the first objective, TTI researchers collected vehicle classification data from Georgia, Texas, Washington, and Colorado. While there were only 36 sites used to investigate potentially new truck distribution graphs, the results indicate that trucks have a different time-of-day distribution than a distribution created from all vehicles together. Because the sample size of these findings is relatively low, researchers hope to investigate these findings on larger samples prior to making methodological changes in the UMR.

To satisfy the second objective, TTI researchers collaborated with public transit experts at the University of South Florida, Center for Urban Transportation Research. Chapter 4 provides several proposed methodological improvements to the transit benefits methodology for the 2013 UMR, including (a) explicitly accounting for the miles traveled by roadway-based transit vehicles operating in mixed traffic conditions, and (b) more accurately accounting for the potential shift to private passenger vehicles in a post-transit environment by transit riders for the passenger miles they have actually traveled by transit. Researchers plan to incorporate these proposed changes into the 2013 UMR. Chapter 4 also documents future improvement opportunities for the short term and long term.

Keywords: Public Transportation, Transit Benefits, Truck Volumes, Urban Mobility Report, Volume Distributions

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An Evaluation of the Effectiveness of Voice-to-Text Programs at Reducing Incidences of Distracted Driving

Christine Yager, Texas A&M University, April 2013, 142 pp.

Text messaging is no longer limited to manual-entry. There are several mobile applications that aim to assist the driver in sending and receiving text messages by incorporating a voice-to-text component. To date, there has been no published research that evaluates the impact of voice-to-text mobile applications on driver behavior and safety. To address this issue, 43 participants drove an instrumented vehicle on a closed course for a baseline as well as three texting conditions: manual-entry, using Siri, and using Vlingo. Results indicate that driver reaction times were nearly two times slower than the baseline condition, no matter which texting method was used. Eye gazes to the forward roadway also significantly decreased compared to baseline, no matter which texting method was used. Additionally, it took drivers longer to complete the same texting task using the voice-to-text applications than it did when texting manually, though Siri produced the fewest errors. Self-assessment feedback revealed that participants felt less safe using any of the three texting methods compared to the baseline, but felt safer using either voice-to-text application than when manually texting. These results have immediate implications for improving our understanding of the dangers of texting while driving and the potential safety improvements of using voice-to-text options.

Keywords: Texting, Voice-to-Text, Speech-to-Text, Distracted Driving, Distraction, Mobile Device Use, Impairment

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Signing Strategies for Low-water and Flood-prone Highway Crossings

Kevin Balke, Laura Higgins, Sue Chrysler, Geza Pesti, Nadeem Chaudhary and Robert Brydia, Texas A&M University, October 2011, 214 pp.

In Texas, approximately eight flood-related fatalities occur each year—the majority of these (78.6 percent) involve motorists that are trapped in their vehicles or washed away. In many cases, victims, not wanting to take a lengthy detour, ignored barricades and tried to drive across a flooded street or low-water crossing—literally driving themselves into harm’s way. It takes as little as 2 ft of water to float most cars. Several districts in Texas have developed different signing strategies for warning motorists of low-water crossings. As part of this research, the Texas Transportation Institute (TTI) developed guidelines and recommendations for creating signing uniformity for low-water and flood-prone sections of roadways. Signing guidelines were created for the following situations: 1) roadway sections that have several low-water crossings where water flows over the roadway in wet conditions, 2) actual low-water crossings, and 3) temporary road closures due to high water. TTI also developed criteria for when to implement active water-level detection and advance warning systems at low-water crossings and flood-prone roadway sections.

Keywords: Ramp Meter, Ramp Control Signal, Warrants, Operational Guidelines

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Evaluating Safety Performance and Developing Guidelines for the Use of Right Turn on Red (RTOR)

Qi Yi, Xiaoming Chen and Da Li, Texas Southern University, December 2012, 59 pp.

This research project investigates the safety performance of Right Turn on Red (RTOR) at intersections. Also, new design alternatives, such as dual right-turn lanes and guidelines incorporating the use of RTOR at intersections are evaluated. To this end, the following tasks were performed: (1) review literature on safety performance of RTOR, (2) review literature on driver behavior under RTOR operation, (3) synthesize best practices and existing guidelines on RTOR, (4) conduct field study to investigate driver behavior under RTOR operation at dual right-turn lanes, and (5) develop guidelines for the use of RTOR.

The results of this study showed that RTOR operations contributed to only a small portion of the total crashes at the intersections, and RTOR operations did not increase the crash rates after the implementation at the intersections. In this study, according to the existing guidelines and the field observation, a set of comprehensive guidelines were developed to support decision-making on the use of RTOR

Keywords: Right Turn On Red, Guidelines, Traffic Safety

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Evaluating the Impacts of the Panama Canal Expansion on Texas Gulf Ports

Robert Harrison and Manuel Trevino, University of Texas at Austin, March 2013, 56 pp.

This report covers a four-year period after contractors started work on the third set of locks, which in 2015 will effectively double the size of the ship using the Panama Canal. Many of the impacts linked to the new locks remain unknown (like lock fees, demand, and shipper response) but it has been successfully promoted as an economic stimulus to a number of the larger Gulf and East Coast Atlantic ports. This in turn has generated a number of studies that reported during 2012. This report concentrates on three issues raised in these reports that fit the resources and focus of the original study—statewide planning. Chapter 2 gives a Texas Gulf perspective on the potential impacts of the new locks. Chapter 3 examines a major, yet unresolved, issue facing shippers and steamship companies – offering “direct” versus “hub and spoke” services to ports that may not have the status of true load centers or sufficiently deep access channels. Finally, Chapter 4 provides planning observations and recommendations, which could strengthen Texas statewide multimodal plans over the next 20 years.

Keywords: Panama Canal, Expansion, New Locks, 2014, Freight, Freight Planning, Texas Gulf, Gulf Coast Ports

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A Comparison of Crashes and Fatalities in Texas by Age Group: Selected Cities in Texas

Gwen Goodwin, Jamaal Schoby and Shain Eversley, Texas Southern University, October 2012, 48 pp.

In recent decades, great strides have been made to lower the number of accidents that occur on Texas roadways through graduated drivers licensing programs, messages against texting and driving, and discouraging drunk driving. Statistics show that young, novice drivers between 16 and 24 years old account for the highest rate of crashes, and senior drivers (65 and older) have the highest rate of fatalities when involved in a crash. In 2008, in Texas, 571 teens died in car crashes. From 2003 to 2008 over 2,751seniors lost their lives in automobile accidents. Building on work done on a previous study of senior fatalities, this study will examine crash data from 2006 and 2009 from the cities of Houston, Sugar Land, and Pearland, Texas to determine if the number of crashes per age group is increasing or decreasing. This study will also determine if fatalities are increasing or decreasing between these two age groups.

Keywords: Senior Accidents, Teen Accidents, Comparing Crashes of Teens and Senior, Young Drivers, Senior Drivers

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Rural Planning Organizations – Their Role in Transportation Planning and Project Development in Texas:  Technical Report

John Overman, Patricia Ellis, William Frawley, Ryan Taylor, Tina Geiselbrecht, and Ginger Goodin, Texas A&M University, October 2010, 154 pp.

While a formal planning and programming process is established for urbanized areas through Metropolitan Planning Organizations, no similar requirement has been established for rural areas.  Currently, under the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users, states are required to consult with non-metropolitan local officials in transportation planning and programming.  The consultation process between state Departments of Transportation (DOT) and non-metropolitan local officials is not prescribed in the planning rules, and consultation practices vary widely among each state’s DOT.

Historically, the Texas Department of Transportation (TxDOT) has worked in cooperation with each individual rural county to plan and program projects.  This has often resulted in a county-by-county project list that the TxDOT districts must try to fashion into a regional strategy or plan.  A need exists to examine the concept of rural planning organizations and research their use in Texas to determine if a formal rural planning organization may offer a means to improve transportation planning and programming.  The objective of this research is to identify and examine rural planning organizations, their structure and operation, and their role in transportation planning and programming.  The project will include a review of current processes used by TxDOT and other agencies to plan and program transportation projects in rural areas.

Keywords: Rural Planning Organization, Rural Transportation Planning

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Operational Performance Management of Priced Facilities

Ginger Goodin, Mark Burris, Timothy Lomax, Tina Geiselbrecht, and Robert Brydia, Texas A&M University, October 2010, 98 pp.

The Texas Department of Transportation and its agency partners have implemented various forms of lane management and pricing over the past three decades, including HOV lanes, managed lanes, and toll roads.  As more of these complex transportation facilities are planned and constructed throughout the state, there is a need to understand how these facilities may operate over time.  Ideally, the long-term operations should be based on metrics that are agreed upon in advance.  By defining what metrics can most effectively measure the performance of a facility and outlining what thresholds trigger a change in operation, policy-makers and the public can anticipate and appreciate how a facility’s operation may change over time.  This understanding allows the facility operators to focus on the tasks of efficiently operating a smooth transportation network rather than focusing on how to get the necessary changes made in a timely manner.  This study provides a framework in which operating decisions for priced facilities can be made and can guide the changes in operational strategies for a facility over time. The research process was initiated with a literature review and targeted interviews of toll and managed lane operators to assess the state of the practice in performance measurement for pricing and other operational changes.   The research team then developed guiding principles for identification, selection, and communication of performance measures and targets.  A conceptual framework was formulated and data collection infrastructure needs were also documented.  The conceptual framework was then developed into a more detailed version in a web-based format.  This report documents the research findings and results and provides guidance on the use of the web-based framework tool.  In addition, several outreach products were developed under this study to assist agencies in communication of performance management principles for proactive management of priced facilities.

Keywords: HOT, HOV, Managed Lanes, Operations, Tolls

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Quantifying the Purchasing Power of Public Transportation in Texas:  Technical Report

Linda Cherrington, Suzie Edrington, Mostafa Malki, Mario Beruvides, James Simonton, Natalie Waters, Siva Chaivichitmalakul, Himlona Palikhe, John Walewski, Texas A&M University, November 2009, 252 pp.

Investments in public transportation in Texas contribute to the state and local economy by improving transportation options, which in turn creates benefits for individuals, businesses, and governments. Many different agencies provide public transportation services in Texas. Each of these agencies buys goods and services on an individual basis. The purpose of this research is to quantify the purchasing power of public transportation in Texas and to estimate the economic impact on state and local economies. The research also documents how cooperative purchasing can leverage buying power to reduce the cost of equipment, goods, and services and reduce the time and expense for administration of procurement activities for public transportation providers. Case study examples illustrate opportunities for public transportation providers to leverage buying power through cooperative purchasing.

Keywords: Public Transportation, Public Transit, Cooperative Purchasing, Economic Impact

ENTIRE REPORT (Adobe Acrobat File – 2.5 MB)

Compendium of Student Papers: 2011 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, May 2012, 180 pp.

This report is a compilation of research papers written by students participating in the 2011 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 21st year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) evaluating the impact of nighttime work zone lighting characteristics on motorists; 2) late night roadway visibility; 3) investigation of the use and pricing of the I-15 express lanes in San Diego; 4) intercity passenger rail access to airports: a case study at the Milwaukee airport; 5) development of a background complexity assessment tool; 6) identifying pavement preservation treatments suitable for performance-related specifications; and 7) arsenic content and retroreflectivity of glass beads used in pavement markings.

Keywords: Lighting, Visibility, HOT Lanes, Value of Time, Dynamic Tolling, Intercity Passenger Rail, Airport Ground Access, Intermodal Transportation, Sign, Background, Complexity, Pavement Preservation; Canonical Correlation Analysis

ENTIRE REPORT (PDF – 7.9 MB)

Using Real Time Traveler Demand Data to Optimize Commuter Rail Feeder Systems

Yao Yu and Randy Machemehl, University of Texas at Austin, August 2012, 111 pp.

This report focuses on real time optimization of the Commuter Rail Circulator Route Network Design Problem (CRCNDP). The route configuration of the circulator system – where to stop and the route among the stops – is determined on a real-time basis by employing adaptive Tabu Search to timely solve a Mixed Integer Program (MIP) problem with an objective to minimize total cost incurred to both transit users and transit operators. Numerical experiments are executed to find the threshold for the minimum fraction of travelers that would need to report their destinations via smart phone to guarantee the practical value of optimization based on real-time collected demand against a base case defined as the average performance of all possible routes. The adaptive Tabu Search Algorithm is also applied to three real-size networks abstracted from the Martin Luther King (MLK) station of the new MetroRail system in Austin, Texas.

Keywords: Commuter Rail Circulator Network Design Problem (CRCNDP), Austin Texas, Tabu Search, Mixed Integer Program

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Free-Floating Carsharing Systems:  Innovations in Membership Prediction, Mode Share, and Vehicle Allocation Optimization Methodologies

Katherine Kortum and Randy Machemehl, University of Texas at Austin, August 2012, 123 pp.

Free-floating carsharing systems are among the newest types of carsharing programs. They allow one-way rentals and have no set “homes” or docks for the carsharing vehicles; instead, users are permitted to drive the vehicles anywhere within the operating zone and leave the vehicle in a legal parking space. Compared to traditional carsharing operations, free-floating carsharing allows much greater spontaneity and flexibility for the user. However, it leads to additional operational challenges for the program.

This report provides methodologies for some of these challenges facing both free-floating and traditional carsharing programs. First, it analyzes cities with carsharing to determine what characteristics increase the likelihood of the city supporting a successful carsharing program; high overall population, small household sizes, high transit use, and high levels of government employment all make the city a likely carsharing contender. Second, in terms of membership prediction, several modeling alternatives exist. All of the options find that the operating area is of key importance, with other factors (including household size, household densities, and proportion of the population between ages 20 and 39) of varying importance depending on the modeling technique. Third, carsharing trip frequencies and mode share are of value to both carsharing and metropolitan planning organizations, and this report provides innovative techniques to determine the number of trips taken and the share of total travel completed with carsharing (both free-floating and traditional). Fourth and finally, an original methodology for optimizing the vehicle allocation issue for free-floating carsharing organizations is provided. The methodology takes a user input for the total number of vehicles and returns the allocations across multiple demand periods that will maximize revenue, taking into account the cost of reallocating vehicles between demand periods.

Keywords: Carsharing; Cars2Go; Binary Logit Metropolitan Modeling; Mode Share Modeling

ENTIRE REPORT (Adobe Acrobat File – 2.4 MB)

Quantification of the Effect of Maintenance Activities on Texas Road Network

Jorge Prozzi and Ambarish Banerjee, University of Texas at Austin, August 2012, 54 pp.

Pavement structures are designed for a finite life, usually referred to as performance period. This performance period is typically between 20 to 25 years for flexible pavements and between 25 and 40 years for rigid pavements. After this period, the pavement is predicted to reach a terminal level in terms of several preset criteria. This performance period can be reached by designing a structure that will withstand the effects of traffic and the environment through the design period or by planning a series of maintenance and rehabilitation activities that will keep the structure above the present terminal levels until the end of the design life is reached.

The objective of this study is to gather data on pavement performance from FHWA’s Long-Term Pavement Performance (LTPP) study. The sections will be selected such that they provide enough time-series information to obtain reliable pavement performance trends. Once the data are collected, the various pavement sections will be modeled using mechanistic-empirical principles and they performance will be predicted. The Mechanistic Empirical Pavement Design Guide (MEPDG) will be used for this purpose. In addition, empirical performance models will be developed to capture the performance (and in particular the differential performance) of the various sections. Once these two types of performance models are available, we will compare the effectiveness of the three types of sections.

Keywords: Pavement Preservation, Rehabilitation, MEPDG, LTPP, SPS-3, SPS-5

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Calibration of HERS-ST for Estimating Traffic Impact on Pavement Deterioration in Texas

Jorge Prozzi, University of Texas at Austin, August 2012, 65 pp.

The Highway Economic Requirements System-State Version (or the HERS-ST) is a software package which was developed by the Federal Highway Administration as a tool for evaluating the performance of state highway systems.  HERS-ST has the capabilities of estimating highway system performance and system needs.  It also has the capability of providing investment strategies required to attain a certain level of system performance.  Some states such as Indiana, North Dakota, New Mexico and Oregon have been able to make extensive use of the software.  New Mexico, for example has used the software to provide an assessment for the state’s long term highway needs by running and evaluating various investment scenarios.  The state of Indiana has used the software package in their Long Range Transportation Plan for assessing future system needs and budget planning.  Texas has expressed interest in the HERS-ST software package, but it has been pointed out that the pavement deterioration model used by the HERS-ST software package to estimate pavement wear is inaccurate.  This study focused on disaggregating the pavement deterioration model used by the HERS-ST to better understand its process with particular emphasis on traffic characteristics.  This report presents a methodology that can be used to calibrate the model for state specific conditions.

Keywords: HER-ST; PSR; Pavement Deterioration Estimation

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Transit Agency Strategies that Encourage Mixed Uses around Stations

Carol Abel Lewis, Sandra Onyejekwe, Darlene Collins and Kenneth McGaughay, Texas Southern University, August 2012, 46 pp.

Transit-oriented development (TOD) is a mixed-use residential or commercial area designed to maximize access to public transportation that often incorporates features to encourage transit ridership.  Varied interests must be represented to implement TOD.  Developers present concepts and financial backing, governments create guidelines or zoning that facilitates TOD, community stakeholders voice desires about their neighborhoods and transit agencies implement the transit improvement that serves as the initial catalyst.  This research focuses specifically on the role of the transit agency in encouraging development proximate to transit and investigates selected transit authorities within the United States to determine what strategies and steps they are taking to facilitate proximate desirable development around their stations.

Keywords: Transit Oriented Development, TOD, Transit Agencies, Mixed-use Communities

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Feasibility of Solar Powered Traffic Signs in Houston – A Step toward Sustainable Control Devices

Khosro Godazi, Alexandra Miller and Ronald E. Goodwin, Texas Southern University, August 2012, 37 pp.

With the economy fluctuating all the time, the federal and some city governments at times spend more money than they take in from taxes. It is important for these governments to find ways to reduce spending while still providing sufficient operations for their constituency.  As the national focus turns to finding alternative energy rather than the reliance of fossil fuels, it is not hard to find ways in which the city can save money. One of these ways is taking advantage of the sun’s energy to power our traffic signals as well as switching the traditional incandescent bulbs to LED. Since the city’s origin, Houston, Texas has been a continuous success in population growth, land expansion, job opportunities, and a leader of industry. The city did not get to be where it is by not staying ahead of the curve. With its 2,450 signalized traffic intersections and a wide range in the number of signals at each one, the city has an opportunity to be a leader in large scale retrofitting in the United States. By retrofitting the signals to solar energy and switching to LED the city will see major energy and cost savings, as well as a significant decrease in maintenance cost and time due to the longer lifespan of the LEDs and solar panels.

Keywords: Solar Energy, Light Emitting Diodes (LED), Intersections, Incandescent Bulbs

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Moving the Concept of Megaregions into Transportation Planning: Workshop Proceedings

Carol Abel Lewis, Sara Land and Bethelhem Afefayane, Texas Southern University, August 2012, 63 pp.

An area of growing dialog among transportation professionals is about megaregions and the affect the concept may have on long range travel demand and the movement of goods and people throughout a state or region.  Megaregion connotes that an individual urban area does not operate singly, but in concert with other urban and rural areas as a comprehensive unit providing and attracting goods and services for the world.  As these complex mobility arrangements occur, planning entities are continuing to conduct more localized scaled activities for their independent urban and rural areas.  Key questions should be asked about whether another planning layer should be added that examines the megaregions and investigates the interrelationships to determine if advantages or efficiencies might be available by considering operation of the complex whole as one unit. Clearly, such an assessment would not negate the smaller, local level planning activities, but may offer the potential to more competitively posture a megaregion in line with the other 40 or so world megaregions.  This work convened a workshop addressing that planning concept.  Workshop participants agreed that planning for the megaregions should be added to the elements included in long range plan development.

Keywords: Megaregions, Regional Planning

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Nanotechnology-Based System for Damage-Resistant Concrete Pavements

Rashid K. Abu Al-Rub, Texas A&M University, August 2012, 124 pp.

The focus of this study was to explore the use of nanotechnology-based nanofilaments, such as carbon nanotubes (CNTs) and nanofibers (CNFs), as reinforcement for improving the mechanical properties of Portland cement paste and creating multifunctional and sensing concrete. Due to their ultra-high strength and very high aspect ratios, CNTs and CNFs have been excellent reinforcements for enhancing the physical and mechanical properties of polymer, metallic, and ceramic composites. Very little attention has been devoted to exploring the use of nanofilaments in the transportation industry, however. Therefore, this study aimed to bridge the gap between nanofilaments and transportation materials. This was achieved by testing the integration of CNTs and CNFs in ordinary Portland cement paste through state-of-the-art techniques. Different mixes in fixed proportions (e.g., water-to-cement ratio, air content, admixtures) along with varying concentrations of CNTs or CNFs were prepared. Different techniques commonly used for other materials (like polymers) were used in achieving uniform dispersion of nanofilaments in the cement paste matrix and strong nanofilament/cement bonding. Small-scale specimens were prepared for mechanical testing in order to measure the modified mechanical properties as a function of nanofilament concentration, type, and distribution. With 0.1% CNFs, the ultimate strain capacity increased by 142%, the flexural strength increased by 79%, and the fracture toughness increased by 242%. A scanning electron microscope was used to discern the difference between crack bridging and fiber pullout. Test results showed that the strength, ductility, and fracture toughness can be improved with the addition of low concentrations of either CNTs or CNFs.

Keywords: Carbon Nanotubes, Carbon Nanofibers, Cement, Dispersion, Fracture, Nano Reinforcements

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Transportation Security Institute: Recruiting Next Generation Professionals

Khosro Godazi, Ronald E. Goodwin and Alexandra Miller, Texas Southern University, August 2012, 34 pp.

The Center for Transportation Training and Research (CTTR), as part of Texas Southern University (TSU), served as host for the 2012 Transportation Security Institute (TSI) in Houston and surrounding area. The 2012 Houston TSI focuses on the mission and objectives of transportation security professionals and introduces a pre-selected group of high school students to the various career opportunities within the profession.

TSI provides a curriculum framework that exposes high school students to the transportation security industry via hands-on technical activities, field trips to transportation facilities, lectures by transportation professionals, and on-site seminars. Furthermore, the primary goal of TSI is to introduce exemplary secondary school students to various career opportunities in transportation security. Secondly, industry professionals will reinforce the importance of mathematics, science, and technology skills in the twenty-first century. Lastly, students will observe how public/private partnerships work to strengthen the link between today’s students and future transportation security professionals.

Keywords: Transportation Security, Transportation Modes, Entrepreneurship, Geographic Information System, STEM-Related Careers

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Automating the Process for Locating No-Passing Zones Using Georeferencing Data

Mehdi Azimi and H. Gene Hawkins, Jr., Texas A&M University, August 2012, 123 pp.

This research created a method of using global positioning system (GPS) coordinates to identify the location of no-passing zones in two-lane highways.  Analytical algorithms were developed for analyzing the availability of sight distance along the alignments of two-lane highways.  The main algorithm was incorporated into a computer model that uses GPS data as the input and produces a method for locating no-passing zones.  The resulting automated system processes GPS coordinates and converts them into easting and northing values, smoothes GPS data, and evaluates roadway alignment for possible sight restrictions that indicate where no-passing zones should be located.

Keywords: Passing Sight Distance, No-Passing Zone, Two-Lane Highways, Vector Operation, Global Positioning System (GPS)

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Comparisons Between Vehicular Emissions from Real-World In-Use Testing and EPA MOVES Estimation

Doh-Won Lee, Jeremy Johnson, Jinpeng Lv, Kristen Novak, and Josias Zietsman, Texas A&M University, July 2012, 50 pp.

This research study developed a methodology to perform mandatory dynamometer vehicular emissions tests on real roads, performed on-road emissions tests, and compared the test results to the estimates using the current EPA emissions estimation model.

Currently, mandatory vehicular exhaust emission tests are performed on chassis or engine dynamometers using the Federal Test Procedure (FTP)/Supplemental Federal Test Procedure (SFTP) drive schedules. Based on the developed real-world in-use emissions testing methodology with using a modified test vehicle, authors could follow the FTP/SFTP drive schedules while the vehicle was driven on real roads, and measure emissions during the in-use on-road FTP/SFTP emissions testing. Emissions from the vehicle during the testing were measured, analyzed, and compared to estimated emissions using the current EPA emissions estimation model, MOtor Vehicle Emission Simulator (MOVES). The authors observed discrepancies between the measured data and the MOVES estimates, especially when associated with cold-start emissions. More detailed analysis results, along with the detailed test methodologies, are provided in this report.

Keywords: Emissions Testing, In-Use, On-Road, FTP, SFTP, Emissions Comparisons, MOVES

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Compendium of Student Papers: 2011 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, May 2012, 180 pp. (476660-00003-4)

This report is a compilation of research papers written by students participating in the 2011 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 21st year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) evaluating the impact of nighttime work zone lighting characteristics on motorists; 2) late night roadway visibility; 3) investigation of the use and pricing of the I-15 express lanes in San Diego; 4) intercity passenger rail access to airports: a case study at the Milwaukee airport; 5) development of a background complexity assessment tool; 6) identifying pavement preservation treatments suitable for performance-related specifications; and 7) arsenic content and retroreflectivity of glass beads used in pavement markings.

Keywords: Lighting, Visibility, HOT Lanes, Value of Time, Dynamic Tolling, Intercity Passenger Rail, Airport Ground Access, Intermodal Transportation, Sign, Background, Complexity, Pavement Preservation; Canonical Correlation Analysis

ENTIRE REPORT (Adobe Acrobat File – 7.9 MB)

Examining the Design and Developmental Factors Associated with Crashes Involving Pedestrians, Cyclists, and Motorists in Urban Environments

Eric Dumbaugh, Wenhao Li, and Kenneth Joh, Texas A&M University, May 2012, 49 pp.

Using a parcel-level database of crash incidence and urban form developed for the San Antonio-Bexar County metropolitan region, this study examined how urban form-related variables affect the incidence of crashes involving pedestrians, bicyclists, and motorists. Arterial thoroughfares, strip commercial uses, and big box stores—which include design features expressly intended to support automobile travel—were found to be associated with significant increases in crashes involving pedestrians, bicyclists, and motorists alike. Population density was found to be associated with increased crash incidence among pedestrians, although this is likely a function of increased crash exposure due to the higher levels of pedestrian activity occurring in higher-density environments. The presence of pedestrian-scaled commercial and retail uses, which is likewise associated with increased pedestrian travel, was nonetheless found to be associated with statistically significant reductions in the incidence of multiple-vehicle, fixed-object, and pedestrian crashes. Given that the developmental risk factors that affect pedestrians, cyclists, and motorists proved to be largely the same, this report outlines potential strategies for addressing urban crash incidence in a comprehensive, multimodal manner.

Keywords: Traffic Safety, Community Design, Urban Design, Planning, Land Use

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Development and Validation of a Testing Protocol for Carbon Sequestration Using a Controlled Environment

Beverly Storey, Derrold Foster, Jeremy Johnson and Jett McFalls, Texas A&M University, May 2012, 46 pp. (476660-00028-1)

Carbon footprints, carbon credits and associated carbon sequestration techniques are rapidly becoming part of how environmental mitigation business is conducted, not only in Texas but globally.  Terrestrial carbon sequestration is the general term used for the capture and long-term storage of carbon dioxide.  For a transportation facility, this occurs through the natural processes of the roadside vegetation and soil.  Texas has a state-maintained highway system of approximately 80,000 linear miles of roadway with more than 1.1 million acres of right-of-way, not including the street systems of cities, towns and local communities.  The majority of these roadways have supporting vegetation within their rights-of-way that usually consists of various combinations of grasses, shrubs and trees.  Roadside carbon sequestration measurement practices typically rely on modeling and in-situ measurements. This project conducted initial testing to develop a method for quantifying plant and soil carbon sequestration capabilities under the controlled conditions of the Texas Transportation Institute’s Environmental and Emissions Research Facility (EERF). Plants and soil were subjected to heavy-duty truck emissions over a six week period.  Samples were analyzed for changes in carbon and nitrogen content over time. Due to the plant injury that occurred during testing, the sequestration capabilities of these plant materials and soils were inconclusive. A comparison of samples taken over the course of the study indicated that the desired results may have been accomplished had the initial exposure in the EERF been reduced to a more moderate level. Modifications to this technique for future research on specific soils and plant materials may help identify plant and soil combinations to maximize roadside carbon sequestration.

Keywords: Carbon Sequestration, Environmental Chamber, Right-of-Way, Roadside Vegetation

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Performance Measures for Metropolitan Planning Organizations

Devin Moore, Tara Ramani, Nicolas Norboge, and Katherine Turnbull, Texas A&M University, April 2012, 82 pp. (161004-1)

Performance measurement is a topic of increasing importance to transportation agencies, as issues with funding shortfalls and concerns about transportation system efficiency lead to a shift in how transportation decision making is carried out. In addition to the increased emphasis on performance-based management and accountability, the role of the metropolitan planning organization (MPO) has also gained much significance. MPOs are unique in their role in bridging the gap between various stakeholders in the transportation planning process, and in the expertise and input they provide for transportation decision making. Thus, MPOs play a very important coordinating role in the transportation planning process.
However, individual MPOs differ vastly from one another and often do not have the authority to raise revenue or allocate funds. MPOs often lack the resources to identify and use performance measures. By the use of proper performance measures, MPOs can help guide the local transportation planning process toward achieving higher-level transportation goals.

The aim of this project is to consolidate available knowledge and provide guidance to transportation agencies, specifically MPOs, to help them incorporate performance measurement relating to transportation planning and operations. This research includes a survey of agency practices and agency needs, development of guidance on effective performance measurement and allied issues of strategic planning, goal setting, and data collection.

Keywords: Performance Measures, Metropolitan Planning Organization

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Predicting Damage in Concrete Due to Expansive Aggregates: Modeling to Enable Sustainable Material Design

Syeda Rahman and Zachary Grasley, Texas A&M University, April 2012, 139 pp. (476660-00027-1)

A poroelastic model is developed that can predict stress and strain distributions and, thus, ostensibly damage likelihood in concrete under freezing conditions caused by aggregates with undesirable combinations of geometry and constitutive properties. Sensitivity of the stress distributions to the aggregate and matrix constitutive parameters are assessed to allow improved concrete design. The proposed model does not account for the viscoelastic stress relaxation and may over-predict the stress results. The model is evaluated experimentally through acoustic emission analysis under freeze-thaw cyclic loading, which reveals that air-entrained concrete may undergo durability cracking (D-cracking) if deleterious materials are present. It is determined that high-porosity, low-permeability aggregates with fine pore structure are the most vulnerable to D-cracking in non-air-entrained concrete, and the destructive tensile stress is generated at the aggregate boundary by the Mandel-Cryer effect. On the other hand, low-porosity, high-permeability aggregates relax the pore liquid pressure rapidly and prove to be beneficial for the non-air-entrained concrete. Reduction in aggregate size is found to be effective in quickly relaxing the tensile tangential stress, which eventually helps mitigate D-cracking of concrete. The difference between the coefficients of thermal expansion of the coarse aggregate and the matrix in which they are embedded should not be too high since it may cause tensile stress at the aggregate boundary or interfacial transition zone. Low water-to-cement mass ratio and addition of pozzolans help increase the bulk modulus, reduce the porosity of the porous body, and improve durability. It is also observed that increase in cooling rate decreases concrete durability under freezing temperatures through the reduction in time available to relax pore pressure buildup and the related tangential stresses in the aggregate and matrix.

Keywords: D-Cracking, Poroelastic, Aggregate Size, Porosity, Permeability, Bulk Modulus, Coefficient of Thermal Expansion, Mandel-Cryer Effect, Acoustic Emission

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Laboratory Evaluation of Friction Loss and Compactability of Asphalt Mixtures

Emad Kassem, Eyad Masad, Ahmed Awed and Dallas Little, Texas A&M University, April 2012, 97 pp. (476660-00025-1)

This study aimed to develop prediction models for friction loss and laboratory compaction of asphalt mixtures. In addition, the study evaluated the effect of compaction level and compaction method of skid resistance and the internal structure of asphalt mixtures. The predictive model for friction loss was developed based on parameters that describe aggregate texture and angularity before and after polishing, aggregate gradation, and polishing cycles in the laboratory. Squared-shape slabs of asphalt mixtures were prepared in the laboratory using a linear kneading compactor and polished using a wheel-polishing device. The frictional characteristics were measured after different intervals of polishing cycles. Mixtures with coarser aggregate gradation were found to have better skid resistance than those with fine aggregate gradation. The friction loss model was found to correlate very well with the experimental measurements.

The predictive model for laboratory compaction of asphalt mixtures was developed based on parameters that describe aggregate shape characteristics, aggregate gradation, binder content, and binder properties at compaction temperatures. The researchers executed intensive laboratory experiments to quantify the effect of these parameters on the compaction of asphalt mixture in the laboratory. Two models that describe slope and intercept of the laboratory compaction curves of asphalt mixtures were developed. These models showed strong correlations between the predicted values and the measured ones. These models provide essential inputs to quantify the compaction effort needed to compact asphalt mixtures.

In the last phase of this study, the researchers evaluated the effect of compaction level and compaction method on skid resistance and internal structure of asphalt pavements. The vibratory roller was found to yield a smoother surface than the static roller. In addition, the results confirmed that the vibratory roller was more effective in reducing the air voids than the static roller. Moreover, the test sections compacted using the vibratory roller had more uniform air void distribution compared to the test sections compacted using the static roller.

Keywords: Asphalt Mixtures, Skid, Friction, Compaction, Texture, Angularity, Micro-Deval, AIMS, Abrasion, Polishing, X-Ray CT

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Development of Warrants for Installation of Dual Right-Turn Lanes at Signalized Intersections

Qi Yi, Xiaoming Chen and Da Li, Texas Southern University, April 2012, 116 pp. (161141-1)

Right-turn lanes provide space for the deceleration and storage of right-turn vehicles, and separate turning vehicles from through movements. Dual right-turn lanes are increasingly used at urban intersections primarily for two reasons: (1) to accommodate high right-turn demands and avoid turn-pocket overflows, and/or (2) to prevent right-turn vehicles that exit from a nearby upstream freeway off-ramp (on the left of the roadway) from abruptly changing too many lanes toward the right-turn lane at the intersection.   In addition, a number of other factors may affect the decisions on the installation of dual right-turn lanes.  However, warrants for dual right lane installation are almost non-existent, leaving traffic engineers to rely on engineering judgment.   This research aims to develop warrants for installation of dual right-turn lanes at signalized intersections. Both the operational and safety benefits/costs were analyzed by surveying traffic engineers and by conducting traffic simulation-based analysis.  Microscopic traffic simulation model, VISSIM, was used to quantify the operation benefits and Surrogate Safety Assessment Model (SSAM) developed by Siemens was used to analyze the safety gains due to installation of dual right-turn lanes.

Keywords: Dual Right Turn Lanes; Warrants; Microscopic Traffic Simulation; Traffic Safety

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Fracture Properties and Fatigue Cracking Resistance of Asphalt Binders

Arash Motamed, Amit Bhasin and Anoosha Izadi, University of Texas at Austin, March 2012, 62 pp. (161122-1)

Several different types of modifiers are increasingly bring used to improve the performance of asphalt binders or to achieve desired mixture production characteristics (e.g., Warm Mix Asphalt). However, current Superpave performance specifications do not accurately reflect the performance characteristics of these modified binders. The main objective of this study was to evaluate the inherent fatigue cracking resistance of asphalt binders in the form of a matrix with rigid particle inclusions. The underlying rationale for this approach was to subject the binders to a state of stress that is similar to the one in a full asphalt mixture. This was achieved by fabricating and testing composite specimens of the asphalt binders and glass beads with a specified gradation. Four asphalt binders with similar true temperature grades but different modifiers were used in this study. The viscoelastic and fatigue cracking characteristics of the binders were measured using the glass bead-binder composite specimens in a dynamic shear rheometer at an intermediate temperature. The results demonstrate that the four asphalt binders modified using different methods had different damage characteristics despite the fact that these four binders were rated to have a similar performance grade based on the Superpave specifications. Fatigue cracking characteristics of the glass beadbinder test specimens used in this study were qualitatively very similar to the fatigue cracking characteristics of full asphalt mixtures using the same binders. The rank order of fatigue cracking resistance for the four glass bead-binder mixtures compared reasonably well to the rank order of fatigue cracking resistance for the full asphalt mixtures that incorporated these asphalt binders.

 

Keywords: Asphalt Binder, Fatigue Cracking, Fracture

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Getting the Parking Right for Transit-Oriented Development

Ming Zhang, Katie Mulholland, Jane Zhang, and Ana J. Gomez-Sanchez, University of Texas at Austin, March 2012, 154 pp. (161027-1)

Increasingly MPOs in Texas are incorporating Transit-Oriented Development (TOD) or similar concepts into their long-range plans for the purpose of achieving sustainable transportation. One major challenge to implementing these TOD-type strategies is parking. The conventional parking policies likely produce excessive parking, undermining the expected community benefits of TOD and could even cause the TOD initiative to fail. Getting the parking right is essential to ensure the desirable form and functionality of TOD. There are few studies of the topic on Texas cities. The main objective of this study is to report the state-of-the-knowledge on parking regulations and practice influencing the planning, design, and implementation of TOD. The report first offers a narrative review of the published works on TOD-Parking. Based on the review findings it then presents a matrix of best parking practices for TOD. Finally, the report provides an annotated bibliography of TOD-Parking studies. Appendix 1 assembles parking regulations and practice policies in selected cities in the Austin-Round Rock Metropolitan Statistical Area.

 

Keywords: Parking, Transit-Oriented Development, Pricing, Zoning, Austin-Round Rock MSA

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Equity Evaluation of Vehicle Miles Traveled Fees in Texas

Mark Burris and Lisa Larsen, Texas A&M University, March 2012, 177 pp. (161105-1)

The Texas state gas tax has been 20.0 cents per gallon since 1991, and the federal gas tax has been 18.4 cents per gallon since 1993.  The gas tax is not only stagnant, but depreciating in value due to inflation.  One proposed alternative to the gas tax is the creation of a vehicle miles traveled (VMT) fee; with equity being a crucial issue to consider.

This research used 2009 National Household Travel Survey (NHTS) Texas data to consider the equity impacts surrounding four VMT fee scenarios.  Data were filtered and weighted to reflect results representative of Texas vehicle-owning households in 2008.  Each scenario was run both statically and dynamically under the assumption that the VMT fee would replace the state gas tax.  Results indicate that all of the VMT fee scenarios are essentially as equally vertically equitable as the current state gas tax system.

Keywords: Vehicle Miles Traveled Fee, Equity, Transportation Planning

ENTIRE REPORT (Adobe Acrobat File – 1.4 MB)

Identification of Priority Rail Projects for Texas – Initial Methodology/User Manual and Guidebook

Curtis A. Morgan, Annie Protopapas, Ph.D., P.E., Jeffery E. Warner, Todd B. Carlson, Jun (Jade) Huang, Ying (Sabrina) Li, Leslie E. Olson, Texas A&M University, February 2012, 110 pp.

This project developed a system of evaluative tools for the Texas Department of Transportation (TxDOT) to prioritize its investments in rail-related projects on a statewide basis.  This work is meant to ensure that the limited available funding for rail projects is applied in the most beneficial and efficient manner and is focused upon addressing TxDOT’s strategic goals.  From the findings, researchers recommend a transparent methodology for evaluating proposed rail projects and establishing an initial process through which rail-related investments can periodically be re-evaluated.

Existing project ranking tools were examined and assessed in order to determine opportunities for direct application or adaptation toward TxDOT uses and objectives.  A set of performance-based criteria for TxDOT-funded rail projects were developed in the course of the project and adopted into the 2010 Texas Rail Plan.  A guidebook to assist local and regional planners in routinely executing the methodology with an example case study project evaluation is also included in the report.  Further refinement of the prioritization process will take place under TxDOT’s Short Term Rail development process in accordance with the Texas Rail Plan.

Keywords: Rail, Project Prioritization, Rail Funding

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Potential Connected Vehicle Applications to Enhance Mobility, Safety, and Environmental Security

Xiaosi Zeng, Kevin Balke, and Praprut Songchitruksa, Texas A&M University, February 2012, 83 pp. (161103-1)

The connected vehicle research initiative is the core of the U.S. Department of Transportation’s intelligent transportation system research program. The initiative is beginning to gain momentum in the research community because of the development of a promising wireless communications technology—dedicated short-range communications. Connected vehicle technology has the potential to transform the transportation industry and significantly improve the quality of life of drivers. This study aims to explore the potential uses of connected vehicle technology in real-world settings.

Researchers first conducted a comprehensive review of the state-of-the-art connected-vehicle research and technologies. Once researchers had a thorough understanding of the technology, they focused on selecting and developing the near-term practical applications that use connected vehicle technology. The research team then sought expert opinions from the Texas Transportation Institute working group during two brainstorming sessions, which produced two lists of potential applications and prioritized the applications based on deployment feasibility. In particular, a total of five applications were selected for development of the full concept of operations, including two in safety, two in mobility, and one in environmental security. These applications address various problems, including wrong-way driving and unprotected-grade-crossing crashes (safety); work-zone merge efficiency and safety, and freeway speed harmonization (mobility); and slippery-pavement-related crashes (environmental security).

Keywords: Connected Vehicle, Safety, Mobility, Environment, Intelligent Transportation System, Dedicated Short-Range Communications, Concept of Operations

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The Design of a Comprehensive Microsimulator of Household Vehicle Fleet Composition, Utilization, and Evolution

Rajesh Paleti, Naveen Eluru, Chandra R. Bhat, Ram M. Pendyala, Thomas J. Adler, Konstadinos G. Goulias, University of Texas at Austin, January 2012, 46 pp. (161120-1)

The report describes a comprehensive vehicle fleet composition, utilization, and evolution simulator that can be used to forecast household vehicle ownership and mileage by type of vehicle over time. The components of the simulator are developed in this research effort using detailed revealed and stated preference data on household vehicle fleet composition, utilization, and planned transactions collected for a large sample of households in California.  Results of the model development effort show that the simulator holds promise as a tool for simulating vehicular choice processes in the context of activity-based travel microsimulation model systems.

Keywords: Vehicle Fleet Composition, Household Vehicle Ownership, Vehicle Transactions and Evolution, Transportation Demand Forecasting, Disaggregate Microsimulation, Behavioral Choice Model

ENTIRE REPORT (Adobe Acrobat File – 343 KB)

Reviewing, Analyzing and Updating Marketing Strategies to Increase Public Transit Ridership

Carol Abel Lewis, Grace Arthur, Sandra Onyejekwe, Texas Southern University, January 2012, 48 pp. (476660-00050-1)

Ridership in the United States has been fluctuating over the last decade. With fuel prices increasing, urban and suburban communities growing and global warming and environmental impact getting special attention, it is important to increase our knowledge of best marketing practices to attract riders to public transit as a better alternative to the use of their own car. Houston METRO is adding roughly 30 miles of light rail, offering new quick line bus routes and in general improving efficiency and reducing costs. But in order to move people out of their cars for all or some of their travel, a deeper analysis of the decision variables and a strategy to promote public transit is required.

 

Keywords: Marketing Transit Ridership; Public Transportation Ridership

ENTIRE REPORT (Adobe Acrobat File – 632 KB)

How Fast is a Fast Train? Comparing Attitudes and Preferences for Improved Passenger Rail Service among Urban Areas in the South Central High-Speed Rail Corridor

Benjamin R. Sperry and Curtis A. Morgan, Texas A&M University, December 2011, 89 pp. (161003-1)

High-speed passenger rail is seen by many in the U.S. transportation policy and planning communities as an ideal solution for fast, safe, and resource-efficient mobility in high-demand intercity corridors between 100 and 500 miles in total endpoint-to-endpoint length.  As the nation moves forward with a significant investment to improve its intercity passenger rail system, a number of planning and policy barriers still exist, making it difficult to fully realize the anticipated benefits of high-speed passenger rail.  Using data from an Internet-based survey of residents in three communities in Central Texas—Waco, Temple, and Hillsboro—this research project examined the potential impacts of new intercity passenger rail service on small- or medium-sized communities located in the intermediate area between two larger urban areas that form the endpoints of a federally designated intercity high-speed rail corridor.  Responses from more than 1,000 surveyed residents found that residents’ attitudes toward new intercity passenger rail service are generally favorable and that trains could be used instead of automobiles for some intercity trips.  The project’s findings provide a foundation for later investment-grade ridership studies in the corridor and have potential applications in planning for intercity passenger rail and transportation policy development.

 

Keywords: Intercity Passenger Rail, High-Speed Passenger Rail, Passenger Rail Planning

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

Predicting the Market Potential of Plug-in Electric Vehicles Using Multiday GPS Data

Mobashwir Khan and Kara Kockelman, University of Texas at Austin, December 2011, 45 pp. (161123-1)

Detailed GPS data for a year’s worth of travel by 255 households from the Seattle area were used to investigate how plug-in electric vehicle types may affect adoption rates and use levels. The results suggest that a battery-electric vehicle (BEV) with 100 miles of range should meet the needs of 50% of one-vehicle households and 80% of multiple-vehicle households, if those households fully charge their BEVs just once a day and are willing to use a different vehicle or mode of transport just 4 days a year or less (to serve daily travel distances above 100 miles). Moreover, the average one-vehicle household in the Seattle region relies on its vehicle for 23 miles per day and should be able to electrify close to 80% of its miles using a plug-in hybrid electric vehicle (PHEV) with 40-mile all-electric-range. Households owning two or more vehicles can electrify 50 to 70% of their household miles using a PHEV40, depending on how they assign the vehicle across their drivers each day. Cost comparisons between the average single-vehicle household owning a Chevrolet Cruze (regular gasoline vehicle) versus a Chevrolet Volt PHEV suggest that when gas prices are $3.50 per gallon and electricity rates at the U.S. average of 11.2 ct per kWh, the Volt will save the household $535 per year in operating costs. Similarly, the Toyota Prius PHEV, when compared to the Toyota Corolla, will provide an annual savings of $538 per year.

 

Keywords: Plug-in Electric Vehicles, All-Electric Range, Battery-electric Vehicles, Vehicle Use and Cost

ENTIRE REPORT (Adobe Acrobat File – 756 KB)

 

Evaluating the Effect of Street Network Connectivity on First/Last Mile Transit Performance

Luca Quadrifoglio and Shailesh Chandra, Texas A&M University, November 2011, 64 pp. (161106-1)

This study defines a novel connectivity indicator (CI) to predict transit performance by identifying the role that street network connectivity plays in influencing the service quality of demand responsive feeder transit services. This new CI definition is dependent upon the expected shortest path between any two nodes in the network, includes spatial features and transit demand distribution information, and is easy to calculate for any given service area. Simulation analyses over a range of networks are conducted to validate the new definition. Results show a desirable monotonic relationship between transit performance and the proposed CI, whose values are directly proportional and therefore good predictors of the transit performance, outperforming other available indicators typically used by planners. This study also presents a methodology to identify and locate critical links in a grid street network system of any size for feeder transit services. A critical link can be defined as that link that when eliminated from or appended to an existing network would cause the largest change in the network connectivity and consequently transit performance. Easily computable formulas are provided and validated by simulation analyses. Useful insights indicate a monotonic decrease in link criticality as we depart from the centrally located links to those located at boundaries.

 

Keywords: First/Last Mile, Demand Responsive, Connectivity, Critical Link, Insertion Heuristic

ENTIRE REPORT (Adobe Acrobat File – 781 KB)

An Alternative Transportation Fuels Update: A Case Study of the Developing E85 Industry

Sharon Lewis and Papa S. Travare, Texas Southern University, October 2011, 54 pp. (167360-1)

As the United States imports more than half of its oil and overall consumption continues to climb, the 1992 Energy Policy Act established the goal of having “alternative fuels” replace at least ten percent of petroleum fuels used in the transportation sector by 2000, and at least thirty percent by 2010. Currently, alternative fuels consumed in Alternative Fuel Vehicle (AFVs) account for less than one percent of total consumption of gasoline. This paper examines how alternative fuel E85 can be used to reverse that trend. In addition, this research paper will take a look at some of the ongoing government decisions concerning the use of the alternative fuel E85, and will discuss what policy makers might hold for the future in terms of the supply and demand of alternative fuels in the United States.  This case study will be useful to all stakeholders involved in the transportation industry, including, but not limited to the government, policy makers, automakers, motorists, and researchers, eager to find a just balance with both a better transportation system and a healthy and clean environment.

 

Keywords: Alternative Fuels, E85

ENTIRE REPORT (Adobe Acrobat File – 406 KB)

Opportunities and Challenges for High-Speed Rail Corridors in Texas

Todd Carroll and C. Michael Walton, University of Texas at Austin, September 2011, 189 pp. (476660-00076-1)

Texas features a growing economy and population. The state boasts a large and well-developed network of roads, freight railroads, and air facilities, which make the state a vital link in the movement of people and goods. However, as the state continues to grow in population and economic significance, these systems are straining to meet state, national, and even global needs. It is increasingly obvious to residents and state officials that Texas should consider implementing alternative modes of transport, including development of passenger rail, for which Texas currently lags behind many of its peer states. Passenger rail provides quantifiable benefits in displacing less energy-efficient and higher pollutant-emitting air and automobile modes while generating potential positive economic impacts and enhancing consumer choice and multimodalism. Conveniently, renewed national interest in rail has invigorated research measuring the applicability of passenger rail services to many different regions of the United States, with the possibility that future national transportation visions will include passenger rail as an essential element. This thesis seeks to clarify the potential for passenger rail specifically in Texas through comparison and contrast with other regions and nations in the midst of new national-level knowledge and the changing transportation opportunities and challenges facing the state. Some of the ideal characteristics of successful international passenger systems exist in Texas, including optimal city spacing and a well-established rail network, which have fuelled ongoing interest demonstrated by various system proposals for high-speed intercity transportation in Texas over the last four decades. Despite these characteristics, the state presents a number of barriers to rail transport rooted in low transit use coupled with generally lower density and ambivalent support from politicians and residents when officials present realities of eminent domain and land use changes. However, with revitalized national rail interest and new federal rail planning requirements, the state may yet be able to work through these challenges to exploit the opportunities the state possesses.

Keywords: High-speed, Texas, Rail, Passenger Rail, Planning, Corridors

ENTIRE REPORT (Adobe Acrobat File – 7 MB)

Developing Infrastructure for Interconnecting Transportation Network and Electric Grid, Seok Kim and Ivan Damnjanovic

Texas A&M University, September 2011, 121 pp. (161006-1)

This report is primarily focused on the development of mathematical models that can be used to support decisions regarding a charging station location and installation problem. The major parts of developing the models included identification of the problem, development of mathematical models in the form of bilevel and stochastic programming problems, and development of a solution approach using a meta-heuristic method. PEV parking building problem was formulated as a bilevel programming problem in order to consider interaction between transportation flow and a manager decisions, while the charging station installation problem was formulated as a stochastic programming problem in order to consider uncertainty in parameters. In order to find the best-quality solution, a genetic algorithm method was used because the formulation problems are NP-hard. In addition, the Monte Carlo bounding method was used to solve the stochastic program with continuous distributions. The results of this study provide managerial implications for developers and operators of parking building.

 

Keywords: PEV, Parking Building,  Charging Station, Decision-Support Model, Transportation Network, Electric Power Network

ENTIRE REPORT (Adobe Acrobat File – 6.2 MB)

Managing Commodity Risks in Highway Contracts: Quantifying Premiums, Accounting for Correlations Among Risk Factors, and Designing Optimal Price-adjustment Contracts

Xue Zhou and Ivan Damnjanovic, Texas A&M University, September 2011, 174 pp. (161104-1)

It is a well-known fact that macro-economic conditions, such as prices of commodities (e.g. oil, cement and steel) affect the cost of construction projects. In a volatile market environment, highway agencies often pass such risk to contractors using fixed-price contracts. In turn, the contractors respond by adding premiums in bid prices. If the contractors overprice the risk, the price of fixed-price contract could exceed the price of the contract with adjustment clauses. Consequently, highway agencies have opportunity to design a contract that not only reduces the future risk of exposure, but also reduces the initial contract price.

The main goal of this report is to investigate the impact of commodity price risk on construction cost and the optimal risk hedging of such risks using price adjustment clauses. More specifically, the objective of the report is to develop models that can help highway agencies manage commodity price risks. In this report, weighted least square regression model is used to estimate the risk premium; both univariate and vector time series models are estimated and applied to simulate changes in commodity prices over time, including the effect of correlation;  while genetic algorithm is used as a solution approach to a multi-objective optimization formulation. The data set used in this report consists of TxDOT bidding data, market-based data including New York Mercantile Exchange (NYMEX) future options data, and Engineering News-Record (ENR) material cost index data. The results of this report suggest that the optimal risk mitigation actions are conditional on owners’ risk preferences, correlation among the prices of commodities, and volatility of the market.

 

Keywords: Unit Cost, Contracting, Escalation Clauses, Pricing Risk

ENTIRE REPORT (Adobe Acrobat File – 1.9 MB)

Investigate Existing Non-Intrusive (NII) Technologies for Port Cargo Inspections

Qi Yi, Yasamin Salehi and Yubian Wang, Texas Southern University, September 2011, 61 pp. (161042-1)

The quantity of cargo handled by United States ports has increased significantly in recent years. Based on 2004 data, almost 2.7 billion tons of cargo passed through the ports in one year. To protect the U.S., all of this cargo must be inspected by U.S. Customs Border Protection (CBP) officials in the most effective manner possible. Existing non-intrusive inspection (NII) technologies have significant strengths, but they also have some weaknesses, such as a low detection rate and a long inspection time. Fortunately, there are newer and more advanced technologies that can be used to inspect cargo with higher accuracy and less delay. The goal of this research was to identify the most effective and efficient combination of NII technologies for inspecting cargo arriving at U.S. ports. For this purpose, a discrete-event simulation model was developed to simulate the cargo inspection procedure. By simulating the operations of different combinations of NII technologies, the effectiveness and efficiency of the various combinations were evaluated. This information was used to provide recommendations about the most effective and efficient combinations of NII technologies for detecting a wide range of contraband. The results of this research are helpful in making decisions concerning the appropriate choices of NII technologies for use in inspecting cargo that is entering U.S. ports.

 

Keywords: Non-intrusive Inspection (NII), Advanced Spectroscopic Portals (ASP), Passport Systems (PS), Arena Model, Discreet Simulation

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Senior Automobile Crashes and Fatalities in Texas: Are Older Texas Driver Safe?

Anthony Price and Gwendolyn C. Goodwin, Texas Southern University, September 2011, 35 pp. (476660-00049-1)

Many factors can contribute to a senior being involved in a traffic accident, i.e. poor vision, declining health, roadway hazards, and declining driving skills, etc. Throughout the US, laws are being enacted to ensure that seniors can continue driving without harming themselves or the general public. Katie’s Law (H.B. 84) represents an attempt to make roadways safer for senior drivers in Texas. Katie’s Law requires that elderly persons age 79 and over must renew their licenses in person at Department of Safety offices. This study examines data from Texas Department of Transportation’s (TxDOT’s) accident records during 2003-2008, to determine if enacting Katie’s law resulted in a decrease in senior fatalities. Finally, the study ends by looking at additional senior friendly transportation initiatives.

 

Keywords: Elderly Drivers, Traffic Accidents, Safety Issues

ENTIRE REPORT (Adobe Acrobat File – 242 KB)

Prioritization of Highway Maintenance Functions Using Multi-Attribute Decision Making with Fuzzy Pairwise Comparison

Wenxing Liu and Zhanmin Zhang, University of Texas at Austin, September 2011, 69 pp. (161128-1)

As is the case for most of the Departments of Transportation in the U.S., the Texas Department of Transportation has been experiencing fluctuations of budget for maintaining and preserving its highway infrastructure over the recent years. If the maintenance budget shortfall lasts for an extended period of time, the condition of the highway network would be harmed directly or indirectly since some maintenance work would be deferred or cancelled. Thus, in order to control and minimize the risk caused by maintenance budget reductions, it is important for highway agencies to adjust their maintenance and rehabilitation policies to accommodate budget fluctuations. This report presents a methodological framework that helps highway agencies quantify the risks to highway networks, and revise the highway routine maintenance work plans to minimize the impact of budget fluctuations. The proposed methodology aims to assist highway agencies in prioritizing and selecting maintenance functions according to the risk of not performing a specific maintenance activity. Also, this methodology considers the subjective nature of decision makers’ assessments, allowing different levels of confidence and different attitudes toward risk to be captured as the uncertainty and imprecision involved in the decision making process. In the case study, the proposed methodology is tested with a set of data obtained from the Texas Department of Transportation. The result is compared with the outcome obtained from the crisp Analytical Hierarchy Process using the same set of data. The outcomes from the two methodologies are very close, validating the effectiveness of prioritizing highway maintenance functions using Multi-Attribute Analysis with Fuzzy Pairwise Comparison.

Keywords: Multi-attribute Analysis, Fuzzy Pair-wise Comparison, Maximizing Limited Budget, Prioritize Routine Maintenance Functions

ENTIRE REPORT (Adobe Acrobat File – 438 KB)

Understanding Emerging Commuting Trends in a Weekly Travel Decision Frame–Implications for Mega Region Transportation Planning

Ming Zhang and Binbin Chen, University of Texas at Austin, September 2011, 67 pp. (161127-1)

National transportation statistics have shown the rise of long-distance, trans-regional commute (LDC/TRC) in the US. Four societal factors contribute to the trend: increase in dual earner households, advance in information and communications technologies, new concept of arranging work time weekly, and people’s changing attitude towards travel. In the field of urban transportation planning, commuting has been studied in individual metropolitan areas in a one-day time frame. LDC/TRC traverse multiple metros and the commuting behavior cannot be better understood without going beyond the one-day convention. Studying LDC/TRC corresponds to the growing interest worldwide in planning for megaregions. Up to date, the phenomenon of weekly commuting has been explored only by a few European researchers in the fields of geography and sociology.

This study analyzed LDC/TRC using national datasets available in the US. They are American Travel Survey, National Household Travel Survey, and Census Transportation Planning Package. Further detailed analyses were conducted for the Texas Triangle megaregion. The national travel surveys are helpful in portraying large pictures of LDC/TRC but limited in offering insights into LDC/TRC behavior. Based on the preliminary study, the next phase of the study will conduct qualitative research by interviewing selected LDC/TRC individuals in the Texas Triangle megaregion.
Keywords: Long-distance Commute, Travel Behavior, Transportation Planning, Texas Triangle, Megaregion

ENTIRE REPORT (Adobe Acrobat File – 654 KB)

Megaregion Freight Movements: A Case Study of the Texas Triangle

Dan Seedah and Robert Harrison, University of Texas at Austin, September 2011, 81 pp. (476660-00075-1)

U.S. population growth is predicted to substantially increase over the next 40 years, particularly in areas with large regional economies forecasted to contain over two-thirds of the national economic activity. In Texas, population growth from 2000 to 2040 is predicted to increase around 72% and produce a diverse population of some 36 million. This will comprise 12% rural and 88% urban, much of it in the 26 metropolitan areas. These population and economic estimates stimulated the exploration of appropriate planning strategies to address the needs of serving such growth, including a macro approach encapsulated in the term megaregions. Although some planners are skeptical about whether this concept enhances traditional planning, it does merit examination in the freight transportation sector, which tends to get less emphasis in community and regional planning. Texas has at least one megaregion, and the largest—The Texas Triangle, comprising Dallas/Fort Worth-San Antonio-Houston—generates over 60% of the gross state product. The project will consider the Texas Triangle with an emphasis on maintaining efficient future freight movement and will offer multimodal solutions to moving freight to, between, and within the metropolitan economies of the megaregion to 2050.

Keywords: Megaregions, Megaregional Planning, Texas Triangle, Freight Transportation, Freight Bottlenecks

ENTIRE REPORT (Adobe Acrobat File – 3.6 MB)

Testing Information to Improve Communication with Communities and Decision Makers

Kadijah Hall and Carol Abel Lewis, Texas Southern University, September 2011, 29 pp. (473700-00055-1)

This work focuses on important concepts in making information available to decision makers and the public, specifically focused on the Transportation Industry. The emphasis is on the PowerPoint presentation and enhancing the message through this medium. Critical elements include adhering to the assigned time limit, incorporating animation, font size, including images, techniques, and preparation.  While much information is available on-line about presentations, audiences at too many transportation meetings view substandard presentations, which likely negatively affect understanding and decision-making.  Blending available information, focus group feedback and observations yield a foundation for transportation planners in improving presentations to constituents.

 

Keywords: Public Presentations, Public Meetings, Information for Decision Makers, PowerPoint Presentations

SUMMARY REPORT (Adobe Acrobat File – 2 MB)

Operational and Vehicular Strategies for Reducing Fuel Consumption and GHG Emissions from Trucking

Melissa Thompson and C. Michael Walton, University of Texas at Austin, August 2011, 99 pp. (476660-00072-1)

Reducing fuel consumption and greenhouse gas emissions is becoming increasingly important in the United States, and new legislation can be expected in the near future that will affect trucks either directly or indirectly. This work is a qualitative examination of operational strategies for reducing fuel consumption from freight trucking, and also compares them with vehicular strategies. A focus is placed on who implements, benefits from, and pays for each strategy, and what type of trucking each strategy is applicable to.

 

Keywords: Emissions, Fuel Consumption, Greenhouse Gas, Heavy Vehicle, Freight

SUMMARY REPORT (Adobe Acrobat File – 800 KB)

High Speed Rail: A Study of International Best Practices and Identification of Opportunities in the U.S.

Beatriz Rutzen and C. Michael Walton, University of Texas at Austin, August 2011, 135 pp. (476660-00071-1)

In the United States, passenger rail has always been less competitive than in other parts of the world due to a number of factors.  Many argue that in order for a passenger rail network to be successful major changes in service improvement have to be implemented to make it more desirable to the user.  High-speed rail can offer such service improvement.

With the current administration’s allocation of $8 billion in its stimulus package for the development of high-speed rail corridors and a number of regions being interested in venturing into such projects it is important that we understand the factors and regulatory structure that needs to exist in order for passenger railroad to be successful.  This study aims to review how foreign countries have developed and their railroad systems to identify key factors that have contributed to its successful implementation.  An evaluation of the factors, such as organization structure, operation, administration, development and type of funding, that are common to each of these projects will used as performance measures to identify potential locations and opportunities for high speed rail projects in the U.S. Southwest region.

Keywords: Passenger Rail, High Speed Rail, Corridors, Operation Management

SUMMARY REPORT (Adobe Acrobat File – 4 MB)

The Economic Efficiency of Allowing Longer Combination Vehicles in Texas

Bridget N. Bienkowski and C. Michael Walton, University of Texas at Austin, August 2011, 77 pp. (476660-00077-1)

This paper shows the economic efficiency of allowing longer combination vehicles in Texas. First, an overview of the truck size and weight policies is explained, with an emphasis on those that affect Texas. Next, LCV operations in other countries are described. Then, an LCV scenario for Texas is chosen, with specific routes and vehicle types. Operational costs for these vehicles are calculated on a cost per mile and cost per ton (or cubic yard) mile. The LCV scenario and the current truck base case are analyzed to find the number of truck trips, the number of mile, and the cost per mile for the chosen routes. These are then compared to estimate the change if LCVs were allowed in Texas.

Keywords: Truck, Trucking, Economics, Policy Freight, LCV

SUMMARY REPORT (Adobe Acrobat File – 1.7 MB)

Taxiway Aircraft Traffic Analysis at George Bush Intercontinental Airport

Kai Yin, Chunyu Tian, Bruce X. Wang, and Luca Quadrifoglio, Texas A&M University, August 2011, 37 pp. (476660-00029-1)

Serving one of the largest metropolitan areas in the United States, the George Bush Intercontinental Airport (IAH) is among the 10 airports with the longest average taxi-out and taxi-in times. The first part of this report assesses the congestion at IAH by analyzing taxi times and flight data during different hours of the day. The capacity of IAH is investigated by examining the number of departing flights on the ground. It reveals that IAH is operating close to the capacity most of the time. Since increasing airport capacity can mitigate the congestion, the second part of this report develops a surface operation model based on the analyzed results to achieve this aim. A mixed integer programming formulation is proposed to optimize the total taxi times by finding the optimal taxi routes and the related schedules. Afterwards, the model is applied to a sample from real data.

Keywords: Airport, Taxi Times, Congestion, Mixed Integer Program

ENTIRE REPORT (Adobe Acrobat File – 278 KB)

 

Evaluation of Mobile Source Greenhouse Gas Emissions for Assessment of Traffic Management Strategies

Qinyi Shi and Lei Yu, Texas Southern University, August 2011, 85 pp. (161142-1)

In recent years, there has been an increasing interest in investigating the air quality benefits of traffic management strategies in light of challenges associated with the global warming and climate change. However, there has been a lack of systematic effort to study the impact of a specific traffic management strategy on mobile source Greenhouse Gas (GHG) emissions. This research is intended to evaluate mobile source GHG emissions for traffic management strategies, in which a Portable Emission Measurement System (PEMS) is used to collect the vehicle’s real-world emission and activity data, and a Vehicle Specific Power (VSP) based modeling approach is used as the basis for emission estimation. Three traffic management strategies are selected in this research, including High Occupancy Vehicle (HOV) lane, traffic signal coordination plan, and Electronic Toll Collection (ETC). In the HOV lane scenario, CO2 emission factors produced by the testing vehicle using HOV lane and the corresponding mixed flow lane are compared.  In the evaluation of traffic signal coordination, total CO2 emissions produced under the existing coordinated signal timing and the emulated non-coordinated signal timing along the same designed testing route are compared.  In the study about ETC, total CO2 emissions produced by the testing vehicle around an ETC station and a Manual Toll Collection (MTC) station located on the same toll road segment are estimated and compared. The results demonstrated that HOV lane, well-coordinated signal timing, and ETC are all effective measures to reduce mobile source GHG emissions, although the level of effectiveness is shown to be different for different strategies.

Keywords: Greenhouse Gas (GHG) Emissions, Vehicle Specific Power (VSP), Traffic Management Strategy, Evaluation Method, Portable Emission Measurement System (PEMS)

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

An Investigation of the Effects of Reading and Writing Text-Based Messages While Driving

Joel Cooper, Christine Yager and Susan T. Chrysler, Texas A&M University, August 2011, 69 pp. (476660-00024-1)

Previous research, using driving simulation, crash data, and naturalistic methods, has begun to shed light on the dangers of texting while driving. Perhaps because of the dangers, no published work has experimentally investigated the dangers of texting while driving using an actual vehicle. Additionally, previous research does not clearly differentiate the dangers associated with reading and writing text messages. To address these issues, 42 participants drove an instrumented research vehicle on a closed driving course. Participants drove under a control, text reading, and text writing condition. Baseline text reading and writing data were also collected outside of the research vehicle. Results indicated that impairment associated with texting while driving may be greater than previously thought. Principally, when reading or writing texts, drivers exhibited reductions in reaction time that were nearly twice as great as previously thought. Drivers also exhibited nearly identical impairment in the reading and writing conditions, suggesting that both reading and writing text messages may be equally dangerous. These results have immediate implications for improving our understanding of the dangers of texting while driving and may be useful for future public policy discussions.

Keywords: Texting, Distracted Driving, Distraction, Mobile Device Use, Impairment

ENTIRE REPORT (Adobe Acrobat File – 1.2 MB)

U.S. and Texas International Trade and Transportation

Leigh B. Boske and Larry K. Anazia, University of Texas at Austin, July 2011, 69 pp. (161121-1)

This report, funded by the Southwest Region University Transportation Center, examines various aspects of international trade, transportation, and foreign practices implemented facilitate and fund transport-related infrastructure. The report is composed of six chapters. The first chapter provides an overview of the U.S. international trade outlook. The second chapter describes the roles played by air cargo transport, ports and ocean carriers, railroads, and the motor carrier industry in U.S. international trade. The third and fourth chapters focus on Texas-specific international trade and modal gateways. The fifth chapter reviews various transport funding mechanisms, Intelligent Transportation System (ITS) applications, and forms of public-private partnerships adopted in various foreign countries. The final chapter describes the expansion of the Panama Canal and its likely Texas impacts.

 

Keywords: International Transportation, Trade Patterns and Forecasts, Modal Outlooks, Foreign Country Profiles and Best Practices, Air Cargo and Oceanborne Freight

ENTIRE REPORT (Adobe Acrobat File – 6 MB)

Impact of Performance Goals on the Needs of Highway Infrastructure Maintenance

Sunny Jaipuria, Zhanmin Zhang, University of Texas at Austin, July 2011, 53 pp. (169208-1)

Although it is widely accepted that establishing suitable performance goal is critical for system maintenance and preservation, a framework that considers the inter-relationship between conflicting objectives of minimum maintenance and rehabilitation costs, deferred maintenance costs, and vehicle operating costs to the users does not exist.  This report proposes a methodological framework that is aimed at assisting highway agencies with the problem of objectively analyzing policy decisions in terms of the performance goals for their highway networks that would minimize the total transport costs to the society. In a case study of the proposed framework, the highway network managed by the Texas Department of Transportation was examined for different performance goals. The results from the case study indicate that setting lower performance goals lead to savings in the M&R needs, but at the same time, they also significantly increase the exogenous costs such as deferred maintenance costs and the vehicle operating costs.

 

Keywords: Performance Goals, Highway Infrastructure, Maintenance, Transport Costs

ENTIRE REPORT (Adobe Acrobat File – 364 KB)

International Air Cargo Operations and Gateways: Their Emerging Importance to the State of Texas

Leigh B. Boske and Hee Deok Cho, University of Texas at Austin, July 2011, 81 pp. (167261-1)

Air cargo transport has become particularly important in today’s expanding global economy for the movement of high-value goods such as electronics, computer components, precision equipment, medical supplies, auto parts, and perishables. Air cargo operations allow fast, frequent, and predictable transit as an increasing number of companies out-source manufacturing to remote locations of the world. Decreasing product cycles for high-value, high-technology goods have made fast delivery to markets essential. In addition, local industries have become global traders, who can reach consumers worldwide.

This report examines the potential of Texas-based airports, especially Dallas-Ft. Worth International Airport and the Houston Airport System, to emerge as international gateways for global trade in general and trans-Pacific trade in particular. The period covered is 2001 to 2006.

The report is composed of four chapters. The first chapter examines global, U.S., and Texas air cargo trends. The second chapter addresses air freight performance and activities at Texas airports. The third chapter discusses the relationship between air cargo/passenger operations and their impacts on local economic development. The final chapter discusses the policy implications for the State of Texas.

 

Keywords: Air Cargo, Cargo Hubs, Trans-Pacific Trade

ENTIRE REPORT (Adobe Acrobat File – 561 KB)

Another Look at the Question of Density and Rail Transit

Carol Abel Lewis and Kadijah Hall, Texas Southern University, July 2011, 22 pp. (473700-00052-1)

Long community discussions about rail often include whether a city’s spatial distribution of housing, employment and other trip generators is conducive to supporting rail transit.  A city’s decision to construct rail transit is based on an array of variables, some of which may indirectly relate to density.   Other variables considered important are number of new riders, operating costs and construction costs.  Although density is not a direct variable in the list of criteria, numerous studies show a positive correlation with ridership, confirming density as an explanation for the number of riders a system will attract.  For that reason, opponents of new rail systems often raise lack of density as reason not to pursue rail.  This research compares density in a few select cities with the accepted transit efficiency performance measure of operating cost per passenger mile to determine whether this statistic is better in more dense cities.

 

 

Keywords: Density, Rail Transit, Transit Performance

ENTIRE REPORT (Adobe Acrobat File – 505 KB)

Hybrid Distribution Trucks: Costs and Benefits

Garrett Anderson and Robert Harrison, University of Texas at Austin, June 2011, 119 pp. (476660-00080-1)

The respective populations of the United States and Texas are expected to significantly increase over to the next several decades, primarily in urban and metropolitan areas. Economists have also predicted that oil prices will rise in real terms during the same period. Air quality is getting worse in a number of metropolitan areas, triggering non-attainment penalties and spurring an interest in cleaner transportation. Incentives and new policies must be adopted to increase the efficiency of the transportation system and thus move freight with a reduced impact on society and the environment. Hybrids can potentially help solve this issue through their increased fuel economy and reduced emissions. This project evaluated a package delivery truck, beverage delivery truck, and a refuse truck. The research determined that the additional cost (with current prices) of the hybrid refuse truck was justified, but not for the other two trucks. The social cost of emissions was also estimated to help justify hybrids’ implementation. With this information, the rate of hybrid truck adoption was estimated for various policy scenarios. The results indicated that a correctly designed incentive program can greatly increase the rate of hybrid adoption and could be justified by the additional social benefits of emissions reduction.

 

Keywords: Hybrid, Distribution, Costs, Benefits, Demand, Fuel Consumption, Freight, Air Quality, Emissions, Texas

ENTIRE REPORT (Adobe Acrobat File – 3.9 MB)

Compendium of Student Papers: 2010 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, June 2011, 254 pp. (476660-00003-3)

This report is a compilation of research papers written by students participating in the 2010 Undergraduate Transportation Scholars Program. The 10-week summer program, now in its 20th year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through
oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) estimating carriers/truckers value of time due to congestion; 2) evaluating retroreflectivity measurement techniques for profiled and rumble stripe pavement markings; 3) analyzing retroreflectivity and color degradation in sign sheeting; 4) evaluating the effectiveness of LED enhanced stop paddles for school crossing guard use; 5) incorporating freight value into the Urban Mobility Report; 6) evaluating ASTM Standard Test Method E2177, retroreflectivity of pavement markings in a condition of wetness; 7) calibrating pavement performance prediction models; and 8) evaluating the effects of concrete curing compounds on hydration.
Keywords: Value of Time, Freight, Trucking, Retroreflectivity, Visibility, Pavement Markings, Traffic Signs, Schools, Pavement Management, Concrete, Hydration

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The Potential for Improving Rail International Intermodal Services in Texas and the Southwest Region of the United States

Robert Harrison and James R. Blaze, University of Texas at Austin, June 2011, 78 pp. (473700-00076-1)

The report covers a period of great significance for railroading in the U.S as it contains a number of milestones now shaping the future performance of the industry. The specific subject is improving intermodal service so that it can support state and regional highway planning, now facing severe financial cut-backs as revenue sources become fully committed to bond servicing, user taxes, loose purchasing power and fuel consumption begins to fall. Intermodal traffic grew strongly in the period 1995 – 2007 and UP and BNSF trans-continental routes were improved largely on the back of intermodal demand. Alliances with larger trucking companies strengthened and transportation officials began to ask whether rail could take some of the predicted freight off key highway corridors. This report addresses elements of this question, more especially as it relates to intermodal traffic in Texas and the Southwest. The report comprises the following sections. Chapter 2 considers the changes in rail freight since the Staggers Act, Chapter 3 evaluates Class 1 intermodal service, and Chapter 4 identifies the major trade corridors serving Texas and the Southern region of the U.S. Chapter 5 describes rail bottlenecks on the state rail system that might impact future intermodal growth, and Chapter 6 concludes by examining the strengths, weaknesses, opportunities and threats to rail intermodal service in Texas and the Southern region over the next decade.

Keywords: Freight rail, Intermodal, Texas Rail Investment, Multimodal Planning

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Optimized Deployment of Emissions Reduction Technologies for Large Fleets

Mohamadreza Farzaneh, Gokhan Memisoglu, Kiavash Kianfar, Texas A&M University, May 2011, 58 pp. (476660-00022-1)

This research study produced an optimization framework for determining the most efficient emission reduction strategies among vehicles and equipment in a large fleet. The Texas Department of Transportation’s (TxDOT’s) fleet data were utilized to identify the key factors as well as refine and demonstrate the developed framework. TxDOT owns and operates more than 11,000 vehicles, of which approximately 3,200 units are non-road diesel equipment. TxDOT is considering serious actions to reduce emissions from its fleet, especially in designated non-attainment (NA) and near non-attainment (NNA) areas. This project includes a comprehensive literature review, identifies the key parameters affecting the deployment of resources to reduce emissions, and develops a framework for producing an optimal emission reduction strategies deployment plan for a typical large fleet.

The capabilities of the proposed framework are demonstrated through a set of five case study scenarios. These scenarios cover a range of location preferences, budget limits, and analysis scales. TxDOT’s fleet data were utilized in this effort. The mathematical formulation and optimization modeling is implemented using ILOG CPLEX and Visual C++ platforms.

 

Keywords: Air Quality, Optimal Resource Allocation, Emission Reduction, Non-attainment, Fleet Operations, PM, NO_x, CO, THC, CO₂

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The Light-Duty-Vehicle Fleet’s Evolution: Anticipating PHEV Adoption and Greenhouse Gas Emissions Across the U.S. Fleet

Binny Paul, Kara Kockleman and Sashank Musti, University of Texas at Austin, May 2011, 195 pp. (161023-1)

The first part of this report relies on stated and revealed preference survey results across a sample of U.S. households to first ascertain vehicle acquisition, disposal, and use patterns, and then simulate these for a synthetic population over time. Results include predictions of future U.S. household-fleet composition, use, and greenhouse gas (GHG) emissions under nine different scenarios, including variations in fuel and plug-in-electric-vehicle (PHEV) prices, new-vehicle feebate policies, and land-use-density settings. This work highlights the impacts of various directions consumers may head with such vehicles. For example, twenty-five-year simulations at gas prices at $7 per gallon resulted in the second highest market share predictions (16.30%) for PHEVs, HEVs, and Smart Cars (combined) — and the greatest GHG-emissions reductions. The strciter feebate policy (pivot point at 30 mpg and fee or rebate rate of $400 per mpg) – coupled with gasoline at $5 per gallon – resulted in the highest market share (16.37%) for PHEVs, HEVs, and Smart Cars, but not as much GHG emissions reduction as the $7 gas price scenario. Excepting the low PHEV price and two feebate policy simulations, all other scenarios predicted a lower fleet VMT. While plug-in vehicles are now hitting the market, their adoption and widespread use will depend on thoughtful marketing, competitive pricing, government incentives, reliable driving-range reports, and adequate charging infrastructure.

The second part of this report relies on data from the U.S. Consumer Expenditure Survey (CEX) to estimate the welfare impacts of carbon taxes and household-level capping of emissions (with carbon-credit trading allowed). A translog utility framework was calibrated and then used to anticipate household expenditures across nine consumer goods categories, including vehicle usage and vehicle expenses. An input-output model was used to estimate the impact of carbon pricing on goods prices, and a vehicle choice model determined vehicle type preferences, along with each household’s effective travel costs. Behaviors were predicted under two carbon tax scenarios ($50 per ton and $100 per ton of CO2-equivalents) and four cap-and-trade scenarios (10-ton and 15-ton cap per person per year with trading allowed at $50 per ton and $100 per ton carbon price). Carbon taxes were found to relatively regressive than a cap-and-trade setting (in terms of taxes paid per dollar of expenditure), but a tax-revenue redistribution can be used to offset this regressivity. In the absence of substitution opportunities (within each of the nine expenditure categories), these results represent highly conservative (worst-case) results, but they illuminate the behavioral response trends while providing a rigorous framework for future work.

 

Keywords: Vehicle Choice, Fleet Evolution, Vehicle Ownership, Greenhouse Gas (GHG) emissions, Plug-In Hybrid Electric Vehicles (PHEVs), Climate Change Policy, Stated Preference, Opinion Survey, Microsimulation

 

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Optimal Infrastructure Maintenance Scheduling Problem Under Budget Uncertainty

Lu Gao, Zhanmin Zhang, University of Texas at Austin, May 2011, 68 pp. (161028-1)

This research addresses a general class of infrastructure asset management problems. Infrastructure agencies usually face budget uncertainties that will eventually lead to suboptimal planning if maintenance decisions are made without taking the uncertainty into consideration. It is important for decision makers to adopt maintenance scheduling policies that take future budget uncertainty into consideration. The author proposes a multistage, stochastic linear programming model to address this problem. The author also develops solution procedures using the augmented Lagrangian decomposition algorithm and scenario reduction method. A case study exploring the computational characteristics of the proposed methods is conducted and the benefit of using the stochastic programming approach is discussed.

Keywords: Stochastic Linear Programming, Lagrangian Algorithm, Infrastructure Asset Management, IAM

 

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Managed Lane Travelers – Do They Pay for Travel as They Claimed They Would?

Mark Burris, Prem Chand Devarasetty and W. Douglass Shaw, Texas A&M University, May 2011, 148 pp. (161002-1)

This study examined if travelers are paying for travel on managed lanes (MLs) as they indicated that they would in a 2008 survey. To achieve the objectives, an Internet-based stated preference (SP) survey of Houston’s Katy Freeway travelers was conducted in 2010. Three survey design methodologies—Db-efficient, random level generation, and adaptive random—were tested in this survey.

Separate mixed logit models were developed from the responses obtained from the three different design strategies in the 2010 survey. The implied mean value of travel time savings (VTTS) varied across the design-specific models. Only the Db-efficient design was able to estimate a value of reliability (VOR). Based on this and several other metrics, the Db-efficient design outperformed the other designs. A mixed logit model including all the responses from all three designs was also developed; the implied mean VTTS was estimated as 65 percent ($22/hr) of the mean hourly wage rate, and the implied mean VOR was estimated as 108 percent ($37/hr) of the mean hourly wage rate.

Data on actual usage of the MLs were also collected. Based on actual usage, the average VTTS was calculated as $51/hr. However, the $51/hr travelers are paying likely also includes the value travelers place on travel time reliability of the MLs. The total (VTTS+VOR) amount estimated from the all-inclusive model from the survey was $59/hr, which is close to the value estimated from the actual usage.

 

Keywords: Survey Design, Managed Lanes, Value of Time, Value of Reliability

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Development of Reliable Pavement Models

José Pablo Aguiar-Moya, Jorge Prozzi, University of Texas at Austin, May 2011, 150 pp. (161025-1)

The current report proposes a framework for estimating the reliability of a given pavement structure as analyzed by the Mechanistic-Empirical Pavement Design Guide (MEPDG). The methodology proposes using a previously fit response surface, in place of the time-demanding implicit limit state functions used within the MEPDG, in combination with an analytical approach to estimating reliability using First-Order and Second-Order Reliability Methods (FORM and SORM). Additionally, in order to assess the accuracy of the FORM and SORM reliability estimates, Monte Carlo simulations are also performed.

A case study based on a three-layered pavement structure is used to demonstrate the methodology. Several pavement design variables are treated as random; these include HMA and base layer thicknesses, base and subgrade modulus, and HMA layer binder and air void content. Information on the variability and correlation between these variables are obtained from the Long-Term Pavement Performance (LTPP) program.

Response surfaces for limit states dealing with HMA rutting failure are fit using several runs of the MEPDG based on a factorial design of combinations among the aforementioned random variables, as well as traffic, structural, and climatic considerations. These response surfaces are then used to analyze the reliability of the given pavement structure.

Using the second moment and simulation techniques, it was found that on average the reliability estimate by the MEPDG is very conservative. Additionally, the validity of the methodology is verified by means of direct simulation using the MEPDG. Finally, recommendations on fitting the response surface are provided to ensure the applicability of the methodology.

Keywords: Mechanistic-Empirical Pavement Design Guide (MEPDG); First-Order and Second-Order Reliability Methods (FORM and SORM); Pavement Structure; Pavement Response

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Designing Fine Aggregate Mixtures to Evaluate Fatigue Crack-Growth in Asphalt Mixture

Anoosha Izadi, Arash Motamed and Amit Bhasin, University of Texas at Austin, April 2011, 54 pp. (161022-1)

Fatigue cracking is a significant form of pavement distress in flexible pavements. The properties of the sand-asphalt mortars or fine aggregate matrix (FAM) can be used to characterize the evolution of fatigue crack growth and self-healing in asphalt mixtures. This study compares the internal microstructure of the mortar within a full asphalt mixture to the internal microstructure of the FAM specimen. This study also conducts a limited evaluation of the influence of mixture properties and methods of compaction on the engineering properties of the FAM specimens. The results from this study, although limited in number, indicate that in most cases the SGC compacted FAM specimen had a microstructure that most closely resembled the microstructure of the mortar within a full asphalt mixture. Another finding from this study was that, at a given level of damage, the healing characteristic of the three different types of FAM mixes was not significantly different. This indicates that the healing rate is mostly dictated by the type of binder and not significantly influenced by the gradation or binder content, as long as the volumetric distribution of the mastic was the same. In other words, the inherent healing characteristics of the asphalt binder plays a more significant role relative to other properties (e.g. volumetrics) in the overall fatigue cracking resistance of the asphalt mixture.

Keywords: Asphalt, Sand-asphalt Mixture, Fine Aggregate Matrix, Fatigue, Self-healing

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The Relationship Between Income and Personal Vehicle Fuel Efficiency and Associated Equity Concerns for the Fuel Tax

Richard T. Baker, Miranda Russ, and Ginger Goodin, Texas A&M University, March 2011, 35 pp. (161007-1)

The fuel tax, which is assessed on the physical amount of fuel purchased by the consumer, is the primary means of funding roadway development at the state and national level. However, because it is assessed on a gallon basis, drivers of vehicles with a low fuel efficiency pay more per mile for use of the roadway than drivers of more fuel efficient vehicles. If there is a relationship between fuel efficiency and income, such that lower income drivers are more likely to drive a low fuel efficiency vehicle, then the equity of the fuel tax is in question. In this study, researchers analyzed over 350,000 vehicle registration records from around the State of Texas to determine if areas with a lower median income had a higher distribution of low fuel efficiency vehicles. Researchers found that vehicles registered in lower income areas tended to have lower average fuel efficiencies than vehicles registered in areas with mid-range and higher income. Lower income areas and rural areas were also more likely to have a higher percentage of class 35 vehicle registrations, usually larger light duty pickup trucks and sport utility vehicles, which tend to have lower fuel efficiency.

 

Keywords: Fuel Tax, Gas Tax, Equity, Vehicle Registration Records

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Creating a Systems Engineering Approach for the Manual on Uniform Traffic Control Devices

Heather McNeal and H. Gene Hawkins, Jr., Texas A&M University, March 2011, 98 pp. (476660-00009-1)

The Manual on Uniform Traffic Control Devices (MUTCD) provides basic principles for use of traffic control devices (TCD).  However, most TCDs are not explicitly required, and the decision to use a given TCD in a given situation is typically made by an engineer (or an individual working under engineering supervision) based on a variety of information including, but not limited to, the MUTCD.  There are many other factors not addressed by the MUTCD that can lead to differences in the decision-making process.  To assist engineers with evaluating these factors, this research developed a decision analysis process to assist engineers with making TCD decisions.  The value of this research is the idea that the decision analysis process for TCD can be modeled and analyzed using appropriate factors including need, impacts, influences, and cost.  This process will contribute to more uniform decisions amongst all levels of experience in TCD decision-making.  When applying this research, it is important to remember that it is not the intent of this process to remove engineering judgment.  This is an important part of the process and should remain as such.

 

Keywords: MUTCD; Traffic Control Devices; Engineering Systems; Decision Analysis; Process for Selecting or Installing Traffic Control Devices

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The Effect of Public Transit on Social Opportunities for Ethnic Minority Populations: Case Study of Huston-Tillotson University Students

Talia M. McCray, Ana Julita Gomez Sanchez, Myung Kyung Chung, University of Texas at Austin, March 2011, 165 pp. (161024-1)

Travel time to destinations in the Austin area continues to rise during both peak and off-peak hours.  With increased congestion and higher gas prices, some individuals are traveling more selectively and viewing public transit as a cost-saving alternative to the automobile.  However, a substantial number of Austinites remain solely dependent on their automobiles for transportation.  This study analyzes the travel patterns of students attending Huston-Tillotson University (HT), an Historical Black College and University (HBCU).  This population does not utilize public transit, and is mostly car dependent.  Reasons given include the need to be independent, the inefficiency of Capital Metropolitan Transportation Authority bus (travel time and routes), condition of bus stops, and the fear of crime while waiting for a bus.   During the Spring of 2009, focus groups were held on HT’s campus, and surveys were distributed to the broader student body.   From September 2009 – May 2010, an environmental analysis of the built environment surrounding 38 bus stops in three locations was performed using an established survey tool.  The researchers determined that both studies were necessary to test whether an environmental analysis would support the findings of the focus groups and student surveys.  Using GIS, a cluster analysis of bus stop environments, and cumulative distribution functions to explore bus travel time to reported destinations, the researchers found that the students’ perceptions were not always consistent with the environmental analysis.  The cluster analysis revealed spatial differences when identifying negative attributes.  However, none of the bus stop structures in the three areas were in very poor condition.  The researchers suggest that a transit training program for HT students would be beneficial in improving ridership.

Keywords: Public Transit, Disadvantaged Populations, Bus Routes, Bus Safety, Environmental Safety Attributes, Cluster Analysis, University Students, GIS, Cumulative Distribution Function, Historical Black Colleges & Universities (HBCUs), Focus Groups, Bus Stops

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An Assessment of Public Involvement for the 2006 Regional Transportation Coordination Planning Process in Selected Texas Cities

Gwen Goodwin and Krystal Lastrape, Texas Southern University, December 2010, 41 pp. (473700-00054-1)

Regional mobility is cumbersome, confusing, and often a frustrating experience for many Texans. Those living in larger urban areas have access to public transportation, while others depend on social service agencies and are required to meet financial and/or medical eligibility criteria.  In some regions, churches and private companies offer limited transport services. Even with the various transportation providers throughout the region and despite federal and state funds spent on transportation, there are still unmet transit needs throughout Texas.

House Bill 3588, is a statewide mandate to coordinate public transportation services and funding among Health and Human Service agencies, Texas Workforce Commission, and the Texas Department of Transportation (TxDOT) at the regional and local levels.  The intent of HB 3588 is to achieve the following:  1) eliminate waste in the provision of public transportation services; 2) generate efficiencies that will permit increased levels of service; and 3) further the state’s efforts to reduce air pollution.  TxDOT commissioners wanted to ensure that the general public and pertinent stakeholders were included in the planning process. This report examines the various public involvement plans and activities implemented by the MPOs and COGs within eight areas, (Austin, East Texas, Corpus Christi, Houston-Galveston, Beaumont, El Paso, North Texas, and San Antonio), as they developed regional coordinated transportation plans.

Keywords: Public Involvement, Public Outreach, Public Involvement in Regional Coordination Transportation Plan

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Use of Micro Unmanned Aerial Vehicles for Roadside Condition Assessment

William Scott Hart and Nasir G. Gharaibeh, Texas A&M University, December 2010, 48 pp. (476660-00019-1)

Micro unmanned aerial vehicles (MUAVs) that are equipped with digital imaging systems and global positioning systems provide a potential opportunity for improving the effectiveness and safety of roadside condition and inventory surveys. This study provides an assessment of the effectiveness of MUAVs as a tool for collecting condition data for roadside infrastructure assets using three field experiments. The field experiments entail performing a level of service condition assessment on roadway sample units on IH-20 near Tyler, Texas; IH-35 near Dallas, Texas; and local streets at the Riverside Campus of Texas A&M University. The conditions of these sample units were assessed twice: on-site (i.e., ground truth) and by observing digital images (still and video) collected via a MUAV. The results of this study will help transportation agencies decide if MUAV technology can be adopted for inventory and condition surveys of roadside assets and maintenance activities.

Keywords: Roadway Level of Service, LOS, Condition Assessment, Roadside Maintenance, Micro Unmanned Aerial Vehicles, MUAV, UAV

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Development of Pedestrian Safety Based Warrants for Permissive Left-Turn Control

Qi Yi and Aohan Guo, Texas Southern University, December 2010, 58 pp. (169302-1)

At the intersections with permissive only signal control, pedestrians will move at the permissive phase with the parallel through vehicular movement and left-turn vehicles, the left-turn vehicles have to yield to both opposing through vehicles and pedestrians at crosswalk. Under such complicated driving conditions, collision risks rise if left-turn drivers make misjudgments and fail to yield to pedestrians. The existing guidelines on left-turn operations mainly focus on the traffic conditions at the intersections and do not give particular considerations to pedestrian safety problems. They are mainly developed based on the left-turn and the opposing through traffic volumes, while the pedestrian volumes and other pedestrian safety related factors, such as design features of the crossroads, direction of sunlight, and the sight distance of the left-turn drivers have not been explicitly taken into account.  Thus, the objective of this research is to develop pedestrian safety based warrants for protected left-turn control. In this research, the driving-simulation based experiments will be conducted for identifying and assessing the impacts of the factors that contribute to the crashes between left-turn vehicles and pedestrians during the permissive left-turn phase, and develop pedestrian safety based warrants.

Keywords: Permissive Left-Turn Control, Pedestrian Safety, Driving Simulator

ENTIRE REPORT (Adobe Acrobat File – 1 MB)

 

Export Growth, Energy Costs, and Sustainable Supply Chains

Dan Seedah and Robert Harrison, University of Texas at Austin, November 2010, 140 pp. (476660-00069-1)

The report examines sustainable supply chains in North America and the role played by rail intermodal operations in lowering ten-mile fuel and emission costs. It examines whether current systems favor imports over exports – a current complaint from some shippers – and whether the development of inland intermodal ports offers a solution to moving future freight into and out of large metropolitan areas. The work is the second of five inter-related UTCP studies examining key changes in intermodal freight transportation in the United States at both national and state levels. It highlights the important role played by rail operations in developing sustainable freight supply chains serving future export and import flows. The major product of the work – a basic rail cost model – serves as a tool to sharpen current metropolitan freight planning and is designed to be enhanced and calibrated by users to address more specific regional issues such as multi-modal corridors.

Keywords: Rail Model, Supply Chains, Freight Transportation, Export Flows, Dry Ports

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Idle Reduction Programs and Potential Benefits to Schools

Michelle Hoelscher, Texas A&M University, November 2010, 161 pp. (476660-00006-1)

School districts in Texas and many other states have, in recent years, increased the “walk zones” surrounding schools to a 2-mile perimeter.  Inside this perimeter, either no school bus service is offered, or service is offered only with a fee to parents.  Many families living in these neighborhoods opt to drive their children to school, resulting in daily traffic congestion in front of schools (and often spilling onto adjacent streets).  The increased vehicle traffic surrounding school facilities presents safety concerns, increases congestion and emissions caused by vehicle idling, and can discourage walking and bicycling even for children living closer to the school.  This project will measure the cost benefits of implementing a school bus idle reduction program as a means to offset the cost of increased bus service.  Increased bus service would provide a less congested school zone thus providing a safer environment for walkers and bike riders living less than 1 mile from school.

Keywords: School Zone, Air Quality, Safety, School Bus Idle Reduction, Parents Idling, Idling Outreach and Education

ENTIRE REPORT (Adobe Acrobat File – 16.2 MB)

Towards and Integrated Pavement Design Approach: Using HWTD to Support the MEPDG

Sergey Grebenschikov and Jorge A. Prozzi, University of Texas at Austin, November 2010, 80 pp. (167274-1)

Variability of hot-mix asphalt (HMA) production can have drastic effects on pavement performance. A poor gradation or an inappropriate amount of asphalt binder could lead to early distresses and shorter pavement life. Other factors, such as the air void content in the asphalt layer, the type of aggregate gradation used in the mix or volumetrics, in general, can also have significant effects on performance.

This research study focuses on analyzing two techniques for observing the variability of mix production and its effects on pavement performance. First, this study focuses on using the Mechanistic-Empirical Pavement Design Guide (MEPDG) to analyze and predict the effect of the variability of HMA production on rutting in the asphalt layer. Then, this study makes an attempt to compare the results produced by the MEPDG with the results produced by the Hamburg Wheel Tracking Device (HWTD). In order to effectively establish correlations between the two techniques, an experiment was conducted during this research. This experiment focused on using volumetric data from a previous research project. The data from this project was used to model asphalt mixes and pavement structures in the MEPDG and the performance results were then compared to actual data obtained in the laboratory from the Hamburg Wheel Tracking Device (HWTD).

The variability of mix production was captured by analyzing three types of limestone mixes: a coarse dense-graded hot-mix asphalt (Type C, according to TxDOT specification), a fine dense-graded hot-mix asphalt (Type D), and a medium graded stone matrix asphalt (SMA-D).  The master gradation band for each mixture was split into three categories: fine, target (actual job mix formula), and coarse. Each mixture was tested at a variable range of binder contents which were obtained using the TxDOT Mix Design Method (TxDOT, 2009). The variability of these mixes and their resistance to rutting as predicted by the MEPDG and measured by the HWTD is discussed in this report.

Keywords: Hot-Mix Asphalt, Asphalt Mix Production, Mechanistic-Empirical Pavement Design Guide (MEPDG), Hamburg Wheel Tracking Device (HWTD)

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An Evaluation of the Effects of Transit Oriented Development in a Suburban Environment

Krystal M. Lastrape and Carol A. Lewis, Texas Southern University, October 2010, 63 pp. (476660-00048-1)

Transit-Oriented Development (TOD) refers to dense, pedestrian-friendly, livable communities that have good transit as a nucleus.  While transit facilities are missing in most suburban towns and the residents are heavily dependent on their vehicles, it is wondered whether residents would take advantage if public facilities were available.  This paper presents information about some vital aspects of TOD when viewed in suburban communities.  The residents in three Houston area suburban communities were studied as to whether they use public transit for work trips via:  (1) light rail (2) commuter bus and (3) express bus.  The comparisons of the three work trip modes and the use of personal automobiles indicate that were transit facilities more available in their community, transit systems would be an effective approach to absorb some growth in trips.  One goal of TOD encourages people to work near home as a way to reduce sprawl and decrease congestion.  A job to housing balance is also assessed.  Creation of better jobs to housing balance would further improve the number of internal trips reducing the use of single-occupancy vehicles.   Enhancements to the convenience of transit, bicycling and walking encourage livable communities by providing safe, convenient and engaging experiences for pedestrians.

Keywords: Suburban Transit Oriented Development, Town Centers, Suburban Mixed Use

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Partnering with AVID to Create Transportation Scholars

Melisa D. Finley and Debbie Jasek, Texas A&M University, October 2010, 44 pp. (169115-1)

The goal of this project was to team with the Advancement Via Individual Determination (AVID) program in local schools to stimulate student awareness of transportation and engineering careers and to encourage interest in the science, technology, engineering, and mathematics (STEM) fields.  AVID is an in-school academic support program for grades 4–12 that prepares underserved students (predominantly minority and economically disadvantaged) in the academic middle for college eligibility and success.  The team developed and conducted four half-day workshops and a field trip for AVID students from four schools in Texas.  Approximately 150 students participated in the half-day workshops and approximately 40 students attended the field trip.  These events offered students an opportunity to gain hands-on experience and insight into transportation and engineering careers.  The events also provided exposure and mentoring from role models that currently work in the transportation field.

 

Keywords: Careers in Transportation, Careers in Engineering, STEM, Transportation Outreach Programs

ENTIRE REPORT (Adobe Acrobat File – 17 MB)

Responses of Trucking Operations to Road Pricing in Central Texas

Beatriz Rutzen, Jolanda Prozzi and C. Michael Walton, University of Texas at Austin, October 2010, 110 pp. (476660-00066-1)

In Texas, where traditional funding lags behind needs to maintain and improve the state’s infrastructure, much of the state’s new highway capacity is being financed through tolls.  With Texas’s major cities already among the nation’s most congested, considerable growth in both population and freight expected, and opportunities for capacity expansion limited by environmental and land-use concerns, it is likely that applications of road pricing to better manage existing capacity will be also necessary in the future.  Little research has been performed to examine truck response to road pricing, and it is clear from the few studies that have been performed that this response is highly variable depending on location, industry sector, commodity type, and trip distance.  The purpose of this study is to identify and quantify how the different segments of the trucking industry would respond to road pricing applications, including traditional toll roads, variably priced toll roads, mixed-use express lane facilities, and truck-only tolled facilities.  Industry variables that will be examined include truck load type, trip distance, commodity, and familiarity with toll roads.

Keywords: Trucks, Commercial Vehicles, Toll Roads, Road Pricing

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Quantitative Characterization of Microstructure of Asphalt Mixtures

Amit Bhasin, Swapneel Badgekar and Anoosha Izadi, University of Texas at Austin, October 2010, 56 pp. (476660-00070-1)

The microstructure of the fine aggregate matrix has a significant influence on the mechanical properties and evolution of damage in an asphalt mixture. However, very little work has been done to define and quantitatively characterize the microstructure of the asphalt mastic within the asphalt mixture. The main objective of this study was to quantitatively characterize the three dimensional microstructure of the asphalt binder within the fine aggregate matrix of an asphalt mixture and compare the influence of binder content, coarse aggregate gradation, and fine aggregate gradation on this microstructure. Results indicate that gradation of the fine aggregate has the most influence of the degree of anisotropy whereas gradation of the coarse aggregate has the most influence on the direction anisotropy of the asphalt mastic within the fine aggregate matrix. Addition of asphalt binder or adjustments to the fine aggregate gradation also resulted in a more uniform distribution of the asphalt mastic within the fine aggregate matrix.

Keywords: Asphalt Mixtures, Fatigue Cracking, Microstructure, X-Ray CT

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Safety and Economic Impacts of Converting Two-Way Frontage Roads to One-Way: Methodology and Findings

William L. Eisele, Christine E. Yager, Marcus A. Brewer, William E. Frawley, Eun Sug Park, Dominique Lord, James A. Robertson and Pei-fen Kuo, Texas A&M University, September 2010, 318 pp. (0-5856-1)

In the research documented here, researchers develop information to communicate the safety and economic impacts of converting frontage roads from two-way to one-way.  Researchers studied five locations in Texas where frontage roads were converted from two-way operation to one-way operation.  Researchers identified a comparison site in Texas that remained two-way for comparison to four of the treatment (conversion) sites.

Researchers developed accident modification factors (AMFs) related to frontage road conversion segments that roadway designers can use to guide frontage road conversion project planning.  Researchers developed AMFs based on non-property-damage-only (non-PDO) crashes for segments and interchange intersections.  Researchers developed 12 AMFs and provide confidence intervals around the estimates.  Researchers describe how the AMFs were developed, associated caveats, and how to apply the AMFs.  Researchers also document the process used to build the safety database from electronic data-sets and printed crash reports.  Finally, researchers provide recommendations to facilitate and expedite future crash analyses.

Researchers attempted to investigate the economic impacts of frontage road conversion by analyzing gross sales data, appraisal data, employment data, and surveys of business owners/managers and customers.  Only the appraisal data and survey information were at the parcel level along the corridors and survey sample size was limited.

 

Keywords: Frontage Road, Frontage Road Conversion, Crash Reduction Factor, CRF, Accident Modification Factor, AMF, Safety, Economic Impact

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Assessment of the Potential of Using Carbon Nanotubes Reinforcements for Improving the Tensile/Fexural Strength and Fracture Toughness of Portland Cement Paste for Damage Resistant Concrete Transportation Infrastructures

Rashid K. Abu Al-Rub and Bryan M. Tyson, Texas A&M University, September 2010, 153 pp. (476660-00011-1)

The focus of this study was on exploring the use of nanotechnology-based nano-filaments, such as carbon nanotubes (CNTs) and nanofibers (CNFs), as reinforcement in improving the mechanical properties of Portland cement paste as a construction material. Due to their ultra-high strength and very high aspect ratios, CNTs and CNFs have been used as excellent reinforcements in enhancing the physical and mechanical properties of polymer, metallic, and ceramic composites. Very little attention has been devoted to explore the use of nano-filaments in the transportation industry. Therefore, this study aimed to bridge the gap between nano-filaments and transportation materials. This was achieved by testing the integration of CNTs and CNFs in ordinary Portland cement paste through state-of-the-art techniques. Different mixes in fixed proportions (e.g. water-to-cement ratio, air content, admixtures) along with varying concentrations of CNTs or CNFs were prepared. Different techniques commonly used for other materials (like polymers) were used in achieving uniform dispersion of nano-filaments in the cement paste matrix and strong nano-filaments/cement bonding. Small-scale specimens were prepared for mechanical testing in order to measure the modified mechanical properties as a function of nano-filaments concentration, type, and distribution.  With 0.1% CNFs, the ultimate strain capacity increased by 142%, the flexural strength increased by 79%, and the fracture toughness increased by 242%.  A scanning electron microscope (SEM) was used to discern the difference between crack bridging and fiber pullout.  Test results showed that the strength, ductility, and fracture toughness can be improved with the addition of low concentrations of either CNTs or CNFs.

 

Keywords: Carbon Nanotubes, Carbon Nanofibers, Cement, Dispersion, Fracture, Nano Reinforcements

ENTIRE REPORT (Adobe Acrobat File – 10.7 MB)

Automated Generation of Virtual Scenarios in Driving Simulator from Highway Design Data

Xi Zhao, Alicia Nelson, Susan Chrysler, and Yunlong Zhang, Texas A&M University, September 2010, 62 pp. (476660-00018-1)

In 2008, the Texas Transportation Institute (TTI) began using a desktop driving simulator made by Realtime Technologies, Inc.  This system comes with a library of different roadway segment types that can be pieced together to create driving scenarios.  The current project explored ways to create custom roadway segments for use in the TTI driving simulator.  The project initially attempted to use AutoCAD^®; Civil 3D^®; roadway drawings and export them for use in the simulator.  This attempt was not successful because all roadway geometric design features could not be exported.  Next, the project used commercially available three-dimensional modeling software (Road Tools by Presagis, Inc.) and was able to create new roadway segments that were drivable in the simulator.  These new roadway segments are not as precise as those created in Civil 3D^®, but for most driving behavior studies conducted in the TTI simulator, researchers judged them to be sufficient.

 

Keywords: Driver Distraction, Vehicle Entertainment Systems, Instrumented Vehicle Research

ENTIRE REPORT (Adobe Acrobat File – 2.3 MB)

Characterizing Information Propagation Through Inter-Vehicle Communication on a Simple Network of Two Parallel Roads

Bruce X. Wang and Kai Yin, Texas A&M University, September 2010, 69 pp. (161005-1)

In this report, we study information propagation via inter-vehicle communication along two parallel roads. By identifying an inherent Bernoulli process, we are able to derive the mean and variance of propagation distance. A road separation distance of times the transmission range distinguishes two cases for approximating the success probability in the Bernoulli process. In addition, our results take the single road as a special case. The numerical test shows that the developed formulas are highly accurate. We also explore the idea of approximating the probability distribution of propagation distance with the Gamma distribution.

Keywords: Network Inter-vehicle Communication, Stochastic Process, Bernoulli Process

ENTIRE REPORT (Adobe Acrobat File – 628 KB)

Transportation for Humanity: Meeting the Needs in the Colonias

Debbie Jasek and Beverly Storey, Texas A&M University, September 2010, 27 pp. (167178-1)

An estimated over 400,000 Texas residents, most of whom are legal citizens of the United States, currently live under poor conditions in colonias along the Texas-Mexico border.  These communities have numerous problems, but one that transcends most other issues is the lack of reliable, safe and affordable transportation, both public and private. The 1996 Texas Colonias Van Project was an innovative initial effort to satisfy the public transportation needs of these unique communities; however, the van project is completed and the vehicles used during its course are depleted and not slated for replacement.

The goal of the research was to assess the current transportation challenges facing residents of the colonias and determine the feasibility of vehicle procurement through donations or at-cost purchases from a variety of entities and/or individuals to support the program, and recommendations for alternative funding mechanisms to support the local community centers in their efforts to provide transportation to the coloniaspopulations.

 

Keywords: Careers in Transportation, Careers in Engineering, STEM, Transportation Outreach Programs

SUMMARY REPORT (Adobe Acrobat File – 776 KB)

Robust Pricing of Transportation Networks Under Uncertainty

Stephen D. Boyles, Lauren Gardner, and S. Travis Waller, University of Texas at Austin, September 2010, 50 pp. (169206-1)

Both public and private entities are concerned with the impacts of future toll revenue, and the effects of tolled facilities on system congestion.  Due to the inherent complexity of transportation systems, it is impossible to predict travel demand and congestion conditions exactly, and simplistic attempts to account for this consistently underestimate true levels of congestion.  Thus, in the context of roadway pricing, there is a need to develop mathematical models which explicitly account for both demand and supply uncertainty in both the short-term and long-term time scales.  This project will develop these models, which will be suitable either to determine the best pricing policies to maximize revenue or minimize congestion, or to evaluate alternative toll policies according to these metrics.  Thus, these models will produce more accurate predictions of toll revenues and congestion levels than are available using current methods.

 

Keywords: Toll Roads, Roadway Pricing, Toll Revenue

ENTIRE REPORT (Adobe Acrobat File – 618 KB)

On Jointly Analyzing the Physical Activity Participation Levels of Individuals in a Family Unit Using a Multivariate Copula Framework

Ipek N. Sener, Naveen Eluru, and Chandra R. Bhat, University of Texas at Austin, September 2010, 62 pp. (161020-1)

The report focuses on analyzing and modeling the physical activity participation levels (in terms of the number of daily “bouts” or “episodes” of physical activity during a weekend day) of all members of a family jointly. Essentially, we consider a family as a “cluster” of individuals whose physical activity propensities may be affected by common household attributes (such as household income and household structure) as well as unobserved family-related factors (such as family life-style and health consciousness, and residential location-related factors). The proposed copula-based clustered ordered-response model structure allows the testing of various dependency forms among the physical activity propensities of individuals of the same household (generated due to the unobserved family-related factors), including non-linear and asymmetric dependency forms. The proposed model system is applied to study physical activity participations of individuals, using data drawn from the 2000 San Francisco Bay Area Household Travel Survey (BATS). A number of individual factors, physical environment factors, and social environment factors are considered in the empirical analysis. The results indicate that reduced vehicle ownership and increased bicycle ownership are important positive determinants of weekend physical activity participation levels, though these results should be tempered by the possibility that individuals who are predisposed to physical activity may choose to own fewer motorized vehicles and more bicycles in the first place. Our results also suggest that policy interventions aimed at increasing children’s physical activity levels could potentially benefit from targeting entire family units rather than targeting only children. Finally, the results indicate strong and asymmetric dependence among the unobserved physical activity determinants of family members. In particular, the results show that unobserved factors (such as residence location-related constraints and family lifestyle preferences) result in individuals in a family having uniformly low physical activity, but there is less clustering of this kind at the high end of the physical activity propensity spectrum.

Keywords: Copulas, Physical Activity, Family and Public Health, Social Dependency, Data Clustering, Activity-Based Travel Analysis

ENTIRE REPORT (Adobe Acrobat File – 788 KB)

Physically Based Model for Predicting the Susceptibility of Asphalt Pavements to Moisture-Induced Damage

Rashid K. Abu Al-Rub, Eyad A. Masad, and Michael A. Graham, Texas A&M University, September 2010, 73 pp. (476660-00012-1)

This study presents a novel moisture-induced continuum damage model for asphalt concrete. Moisture-induced damage is treated realistically as two mechanisms: (1) degradation of the adhesive bond between the asphalt mastic and aggregates and (2) degradation of the cohesive strength of the mastic. The moisture-induced damage model is formulated in a novel way, accounting for the gradual, irreversible degradation of a mix using continuum damage mechanics. Different mechanistic evolution laws are proposed for predicting adhesive and cohesive moisture-induced damage. To the authors’ best knowledge, this model is the first continuum model to capture all facets of realistic asphalt mix response. Moreover, a time- and rate-dependent damage constitutive law is proposed to predict crack nucleation and propagation due to different mechanical loading conditions. The moisture-induced and mechanically-induced damage models are integrated into a three-dimensional nonlinear viscoelastic-viscoplastic constitutive model to allow for more realistic prediction of damage evolution in asphalt concrete under various traffic and environmental loading conditions. Numerical integration algorithms are presented for implementing the model in the well-known finite element code Abaqus. Finally, various aspects of the integrated continuum damage mechanics model are investigated and found to match the qualitative behavior of experiments. The current moisture-induced damage model can be used by pavement engineers to predict the time frame over which moisture-induced damage may occur and to rank asphalt mixtures for moisture damage susceptibility.

Keywords: Moisture Damage Model; Adhesive Moisture Damage; Cohesive Moisture Damage; Viscoelasticity; Viscoplasticity; Finite Element

ENTIRE REPORT (Adobe Acrobat File – 5.6 MB)

Predicting the Incremental Effects on Transit Ridership Due to Bus-On-Shoulder Operations

Eleni Pappas and Randy Machemehl, University of Texas at Austin, August 2010, 87 pp. (476660-00073-1)

Bus-On-Shoulder (BOS) operations are an extremely effective method for increasing the quality of a bus service; allowing for a bus to use a freeway shoulder as a bypass lane not only decreases bus travel time but also increases the bus service’s overall performance.  BOS has also been found to increase bus ridership.  The modern BOS system began in the Minneapolis-Saint Paul area almost 20 years ago.  Using the extensive data available from Minneapolis-Saint Paul, ridership changes due to BOS operations were explored.  The data showed that with 90% confidence, ridership will increase by at least 4.5% and as much as 14.3%.  This report explores how the citizens of Austin, Texas would respond to a BOS operation on local freeways.  A stated preference survey was administered to a sample of Austin commuters. It was determined that potential riders would desire a time savings of 7 or more minutes.  Typically, it is challenging for persons to accurately predict time savings, therefore it was concluded that, for a BOS operation to be successful, it was necessary for there to be a perceived time savings.

 

Keywords: Bus-On-Shoulder, BOS, Bypass Lane, Bus Ridership

ENTIRE REPORT (Adobe Acrobat File – 784 KB)

State Commercial Vehicle Security Enforcement: Operations, Technologies, and Barriers

Alison J. Conway and C. Michael Walton, University of Texas at Austin, August 2010, 66 pp. (473700-00074-1)

This report details the results of a survey of state enforcement agencies concerning past, present, and future enforcement practices and advanced technology use for commercial vehicle security, as well as recommendations for future improvements.  The study examines practices in 19 states, including 7 land border crossing states and 11 states with one or more major marine ports of entry.  Current technology applications, future needs, and past and existing barriers to implementation are all identified.  The study also examines both successes and needs for cooperation between federal, state, and industry stakeholders.  Particular focus is also placed on identifying changes that have occurred since 9/11.

 

Keywords: Commercial Vehicles, Enforcement, Security, ITS

ENTIRE REPORT (Adobe Acrobat File – 410 KB)

A Road Pricing Methodology for Infrastructure Cost Recovery

Alison J. Conway and C. Michael Walton, University of Texas at Austin, August 2010, 296 pp. (476660-00064-1)

The purpose of this research is to provide a theoretical framework for future commercial vehicle user-charging using real-time vehicle weight and configuration information collected using weigh-in-motion (WIM) systems.  This work provides an extensive review of both mechanisms and technologies employed for commercial and passenger vehicle user-charging worldwide.  Existing commercial vehicle-user charging structures use only broad vehicle classifications to distinguish between vehicles for the pricing of user-fees.  The methodology proposed in this study employs highway cost allocation methods for development of an “Axle-Load” toll structure.  A theoretical case study, based on information from Texas State Highway 130, is performed to explore the equity improvements that could be achieved through implementation of this proposed structure.  Some sensitivity analysis is also performed to examine the potential revenue impacts due to uncertainties in different data inputs under existing and proposed structures.

 

Keywords: Trucks, Road Pricing, Cost Allocation, User Charging, Weigh-in-Motion

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Examining the Influence of Tolls on Commute Departure and Route Choice Behavior in the Chicago Region

Naveen Eluru, Rajesh Paleti, and Chandra R. Bhat, University of Texas at Austin, August 2010, 39 pp. (169200-1)

In the United States, a significant number of individuals depend on the auto mode of transportation. The high auto dependency, in turn, has resulted in high auto travel demand on highways. The resulting traffic congestion levels, surging oil prices, the limited ability to address increased auto travel demand through building additional transportation infrastructure, and the emphasis on reducing GHG emissions has led to the serious consideration and implementation of travel demand management (TDM) strategies in the past decade. Congestion pricing is a frequently considered TDM option to alleviate travel congestion in urban metropolitan regions. Congestion pricing might induce changes in activity location, travel route, departure time of day, and travel mode. The current study contributes toward understanding the influence of congestion pricing on commuter behavior by specifically examining what dimensions of commuter travel behavior are affected as a response to congestion pricing. Specifically, we formulate and estimate a joint disaggregate model of commute departure time and route choice drawing from the 2008 Chicago Regional Household Travel Inventory (CRHTI). The empirical analysis demonstrates the significance of individual and household socio-demographics on commuter behavior. The results also highlight how vehicle availability plays an important role in determining individual’s sensitivity to travel time and travel cost. To demonstrate the applicability of the joint modeling framework to determine optimal toll fares, we compute value of travel time measures for different demographic groups.

Keywords: Tolls, Pricing, Route Choice Behavior, Commuter Travel, Departure Time Choice

ENTIRE REPORT (Adobe Acrobat File – 282 KB)

A Comprehensive Examination of Heavy Vehicle Emissions Factors

Melissa Thompson, Avinash Unnikrishnan, Alison J. Conway and C. Michael Walton, University of Texas at Austin, August 2010, 143 pp. (476660-00067-1)

This report summarizes the findings from reviewing the literature on several topics that are related to heavy vehicle emissions including engine and fuel types, vehicle technologies that can be used to reduce or mitigate vehicle emissions, the factors that affect vehicle emissions, vehicle emissions modeling, and current and future policy requiring accurate accounting of heavy vehicle emissions. The pollutants present in diesel exhaust are known to have undesirable effects on both human health and the environment. There are many engine and fuel alternatives for current and prospective vehicle owners to consider that have differing effects on a vehicle’s pollutant output. In addition, new technologies, such as diesel particulate filters, auxiliary power units, and selective catalytic reduction, are being used in the production of new vehicles, and can often be installed on used vehicles, to reduce emissions and/or improve fuel economy. Accurate heavy vehicle emissions modeling is important in forming policies designed to reduce pollutants from heavy vehicle operation at both the vehicle and regional level. Such policies can include cap-and-trade schemes, carbon taxing, and road user charging. All of these policy types have been implemented in the European Union to varying degrees, but only some have been implemented in the United States. However, all of these are now being considered in the U.S., and could be implemented in the future.

 

Keywords: Emissions, Heavy Vehicle, Pollutant, Greenhouse Gas

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

Network Methods for Project Selection Based on Optimizing Environmental Impact

Erin M. Ferguson, Jennifer Duthie and S. Travis Waller, University of Texas at Austin, August 2010, 149 pp. (161026-1)

Traditionally, transportation road networks have been designed for minimal congestion.  Unfortunately, such approaches do not guarantee minimal vehicle emissions.  Given the negative impacts of vehicle pollutants as well as tighter national air quality standards, it is critical for regions to be able to identify capacity modifications to road networks such that vehicle emissions are minimal.  This ability combined with land use changes and opportunities for non-auto travel are paramount in helping regions improve air quality.  However, network design research has yet to directly address this topic.

To fill this apparent gap in network design research, an emissions network design problem and solution method are proposed in this report.  Three air pollutants are considered: hydrocarbons, nitrogen oxides, and carbon monoxide.  The proposed model is applied to two road networks: Sioux Falls, ND and Anaheim, CA.  The model is a bi-level optimization problem solved using a genetic algorithm and incorporates the influence of demand uncertainty.  Findings indicate designing for minimal congestion tends to increase emissions of criteria air pollutants.  However, not adding capacity to a road network also increases emissions of pollutants.  Therefore, an optimization problem and solution method, such as the model presented here, is useful for identifying capacity additions that reduce vehicle emissions.  It is also useful for understanding the tradeoffs between designing a network for minimal congestion versus minimal vehicle emissions.

Keywords: Emissions Network Design, Vehicle Emissions, Road Networks, System Emissions

ENTIRE REPORT (Adobe Acrobat File – 720 KB)

Performance Analysis of the “Zoning” Strategies for ADA Paratransit Services

Luca Quadrifoglio and Chung-Wei Shen, Texas A&M University, August 2010, 53 pp. (169114-1)

ADA paratransit systems are dial-a-ride services providing public transportation to disabled customers. In large metropolitan areas, these services might adopt zoning strategies to simplify their management. The objective of this research is to provide a more in-depth evaluation and comparison between centralized and decentralized zoning strategies for the city of Houston, Texas, by developing a simulation model to evaluate the effect of zoning strategies on the productivity and service quality for the ADA paratransit service. Three decentralized zoning strategies are compared to a centralized no-zoning strategy. Results show that the decentralized “Four-zone” strategy, as opposed to the centralized no-zoning strategy, needs a fleet larger by 17 percent, its empty trip miles are larger by 11 percent, values for the passenger trips per vehicle revenue hour are lower and its average waiting time is 3.7 percent lower.

 

Keywords: Paratransit; Zoning Strategies; Simulation; Service Quality

ENTIRE REPORT (Adobe Acrobat File – 2.6 MB)

Thinking Critically About Models Used to Predict Emergency Evacuation in Gulf Coast States

Carol Abel Lewis, Brandon Moseley and Garlin Wynn, Texas Southern University, July 2010, 42 pp. (476660-00041-1)

Evacuations from Hurricanes Katrina, Rita and Wilma in 2005 illuminated issues with clearing large numbers of residents via urban area roadways and public transportation systems.  In addition, other events including potential terrorists’ attacks or wildfires need to better understand and predict community evacuation. Much work has been done to improve evacuation times and experiences when the need to evacuate occurs.  A number of models exist that forecast evacuation under a variety of scenarios.  This work examines the application of these models in Gulf Coast states and discusses future direction for improving their use by government officials.  Further, an assessment of evacuations during Hurricanes Rita and Ike is included that makes use of an index comparing evacuation travel time to average daily peak travel time.

 

Keywords: Evacuation Modeling, Hurricane Ike Evacuation, Hurricane Rita

ENTIRE REPORT (Adobe Acrobat File – 432 KB)

Examining the Role of Trip Length in Commuter Decisions to Use Public Transportation

Yao Yu and Randy Machemehl, University of Texas at Austin, June 2010, 45 pp. (476660-00074-1)

Traveler trip length has for years been used as a fundamental indicator of the best mix of transit modes and user perceptions of travel cost for transit versus auto. This study examines traveler trip lengths across transit modes, work trip duration frequency distributions and mode share distributions in 7 major cities, 8 Combined Statistical Areas and one Metropolitan Statistical Area and found the effect of increasing population and transit mode variety on work trip travel time and travel distance.

A traditional hierarchy of transit modes arranged by traveler trip length might include local bus, light rail, rapid rail (heavy rail) and commuter rail (regional rail). Based on NTD data, the average trip length for these four modes are: local bus (4.6 miles), light rail (3.9 miles), heavy rail (6.3 miles), and commuter rail (30.1).

Trip Time Frequency Distributions for home-based work trips in all major cities selected in this study followed the same pattern except in New York, NY. In virtually all cities from 1990 to 2005, frequencies decreased in all categories less than 30 minutes and increased in categories greater than 30 minutes. Meanwhile, Trip Time Frequency Distributions for home-based work trips in all selected MSAs also followed the same pattern. These results contradicted our assumption that cities or MSAs with different urban forms or transit history might have different Trip Length Frequency Distributions (TLFDs) and showed that at an aggregated level, there is no statistically significant difference among TLFDs for work trips in the selected areas.

Average work trip length for all the 50 MSAs in National Household Travel Survey data also showed that travel time and travel distance for home-based work trips in all selected MSAs are very similar. Also, from the linear regression functions with trip length as dependent variable, it can be seen that work trip time and distance tend to increase with increasing population, work trip time and distance tend to increase also as the number of transit modes increase.

Keywords: Trip Length, Travel Time, Travel Distance, Work Trip Duration, Transit Modes

SUMMARY REPORT (Adobe Acrobat File – 3.4 MB)

Impacts of Pending Federal Greenhouse Gas Legislation on the Texas Transportation Sector

Leigh B. Boske and James T. Woodward, University of Texas at Austin, May 2010, 55 pp. (161021-1)

This 2010 study, funded by the Southwest Region University Transportation Center, assesses current regulatory attempts to mitigate climate change and how such proposed action would impact the Texas transportation sector economically.  Social and political trends suggest the United States may soon join other United Nations Framework Convention on Climate Change (UNFCCC) countries in drafting substantive, national climate change policy.  After providing a brief overview of past and present climate efforts taken both nationally and internationally, this paper explores different economic solutions to address the externalities of fossil fuel emissions.  Alternatives include command-and-control regulation, a carbon tax, and a cap-and-trade program.  Several factors, including the difficulty of quantifying and constraining greenhouse gas emissions downstream at the vehicle tailpipe, suggest a carbon tax levied upon upstream refiners is the most promising market-based alternative to reduce carbon emissions within the United States’s transportation sector.  Texas business leaders and lawmakers have repeatedly voiced their disapproval of mandatory national carbon controls over the past decade.  A crucial factor why much of the Lone Star State’s populace remains opposed to climate change action is Texas leads the nation’s energy industry, which is decidedly fossil-fuel based and therefore carbon intensive.  Prevailing thought is a carbon tax would only elevate fuel prices increasing the cost of residential and commercial activity heavily dependent on motor vehicles.  This paper articulates how greenhouse gas legislation may financially impact transportation within the Lone Star State and concludes with ways energy and environmental policymakers can build consensus within Texas to address the carbon externality.

Keywords: Climate Change, Greenhouse Gas, Carbon Tax, Transportation, Railroad, Truck, Texas

ENTIRE REPORT (Adobe Acrobat File – 1 MB)

Ant Colony Optimization Algorithm for Signal Coordination of Oversaturated Traffic Networks

Emily Zechman, Luca Quadrifoglio, Rahul Putha, Texas A&M University, May 2010, 58 pp. (169113-1)

Traffic congestion is a daily and growing problem of the modern era in mostly all major cities in the world. Increasing traffic demand strains the existing transportation system, leading to oversaturated network conditions, especially at peak hours.  Oversaturation occurs when queues of vehicles fill the streets approaching intersections and interfere with the performance of adjacent upstream intersections.  Traffic conditions, measured based on the overall throughput of vehicles and total travel time, can be improved by an effective employment of intelligent transportation system techniques.  While a significant amount of research has been devoted to the development of signal control algorithms under normal traffic conditions, a relatively small number of studies have explicitly considered oversaturated conditions.  The overall objective of this study was to investigate the effectiveness of the Ant Colony Optimization (ACO) algorithm in solving the traffic signal control problem under oversaturated conditions.  Due to its ability to reach optimality conditions and identify acceptable solutions efficiently, ACO was a good candidate for a practical use.  This research compared the performance of ACO to that of another heuristic method, the genetic algorithm (GA).  The methods were applied to identify signal control strategies for two example networks.  The results demonstrate that ACO was able to identify fit solutions more reliably than the GA-based approach.

Keywords: Transportation Planning, Traffic Signal Timing, Ant Colony Optimization, Genetic Algorithm

ENTIRE REPORT (Adobe Acrobat File – 747 KB)

PEMS-based Approach to Developing and Evaluating Driving Cycles for Air Quality Assessment

Lei Yu, Ziqianli Wang, and Qinyi Shi, Texas Southern University, April 2010, 94 pp. (169300-1)

A driving cycle is the fundamental concept in conducting emission testing and modeling.  The quality of a driving cycle is directly associated with the accuracy of any air quality analysis, and therefore whether the emission reductions can be achieved.  However, the widely used driving cycles bring considerable uncertainties when the emission estimation is carried out for a specific city or region.  Further, the existing driving cycles have been developed based only on the driving activities, without capturing the characteristics of emission profiles.  In this context, this research is intended to achieve two primary objectives. The first objective is to develop driving cycles for classified roads incorporating both a vehicle’s driving activities and its emission characteristics, using the data collected by Portable Emission Measurement System (PEMS), which was neither available nor has ever been used in developing driving cycles.  A comprehensive database is established for the collected data and a sophisticated computer program is developed to generate the specific driving cycles.  The second objective is to develop an evaluation approach of driving cycles in which Vehicle Specific Power (VSP), a parameter that can readily connect the driving modes with emissions, is used to evaluate how well the driving cycles can represent the driving and emission characteristics on real roads.  The proposed methodology for generating driving cycles is then evaluated for its effectiveness on the emission estimation based on a comparative analysis with the current emission inventory and traditional methodologies.

Keywords: Portable Emissions Measurement Systems (PEMS), Driving Cycles, Driving Activities, Emission Characteristics, Emission Model, Emission Inventory, Vehicle Specific Power (VSP), Evaluation Method

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Climate Change/Variability Science and Adaptive Strategies for State and Regional Transportation Decision Making

Eric Lindquist, Texas A&M University, April 2010, 74 pp. (167165-1)

The objective of this study was to generate a baseline understanding of current policy responses to climate change/variability at the state and regional transportation-planning and ‑decision levels. Specifically, researchers were interested in the question of whether state and regional governments were currently including climate change impacts or vulnerability issues in their decision and planning processes. The focus of this report is on the basic question: are state DOTs and MPOs in the United States addressing the issue of climate change in general and, more specifically, the issue of adaptation to potential climate change and -variability impacts? The research approach included content analysis, an in-depth survey of stakeholders, and interviews with stakeholders. The aggregate findings reveal that acceptance and movement in state DOTs and MPOs on these complex climate-related issues and solutions, where they exist at all, are slow. Mitigating the impacts from transportation appears to still be the primary policy linkage between climate change and transportation for these agencies. Public interest, political acceptance, and lack of downscaled state- and regional-level data are all factors that require further attention in the climate change/transportation nexus.

 

Keywords: Climate Change, Vulnerability, Transportation Planning, Sea-Level Rise, Adaptation

ENTIRE REPORT (Adobe Acrobat File – 684 KB)

Increasing Awareness Among Students About Careers in Transportation

Kadijah Hall, Charles R. Glass, Emmerson W. Edwards, Texas Southern University, April 2010, 23 pp. (476660-00045-1)

This paper focuses on determining the best way to improve the study habits and academic management skills of summer transportation students in grades 9 through 11. To find the most useful teaching method, 12 students were exposed to three learning methods.  Students were taught via field trips, hands-on activities, and lectures. This work describes the program and teaching methods applied.  Further research is required to fully determine which method would be most appropriate for students considering careers in the transportation industry.

Keywords: Field trips, Lectures, Hands-on activities, Teaching

ENTIRE REPORT (Adobe Acrobat File – 106 KB)

Measuring the Benefits of Intercity Passenger Rail: A Study of the Heartland Flyer Corridor

Benjamin R. Sperry, Curtis A. Morgan, Texas A&M University, April 2010, 174 pp. (169116-1)

In recent years, the policy and regulatory environment for intercity passenger rail in the United States has shifted dramatically, sparking a renewed interest in intercity passenger rail among policymakers, planners, and the general public.  As the nation expands its passenger rail network, a better understanding of the mobility provided by short- to medium-distance corridors is desired.  This study examined the Heartland Flyer, a 206-mile intercity passenger rail route between Oklahoma City, Oklahoma, and Fort Worth, Texas.  Researchers analyzed responses to an on-board survey, distributed to passengers in April and July of 2009, to identify who was using the service and how the service impacted regional mobility.  The key measure used to identify the mobility impacts was the passengers’ self-reported alternatives for travel if the Heartland Flyerwere discontinued.  This study also identifies the economic impact of the rail service, measured through total spending on certain items and the associated sales tax revenue).  The findings of this study can be used in a variety of potential applications for all levels of passenger rail planning, including statewide rail planning, corridor-specific studies, and station-area planning, both in the southwestern United States and in other regions.

Keywords: Intercity Passenger Rail, High-Speed Passenger Rail, Amtrak, Heartland Flyer, On-Board Surveys, Passenger Rail Planning, PRIIA, State-Supported Passenger Rail, Intercity Mobility

ENTIRE REPORT (Adobe Acrobat File – 20 MB)

Assessment of Programs that Encourage Students from Diverse Populations to Consider Transportation Careers

Debbie Jasek, Texas A&M University, March 2010, 46 pp. (167175-1)

The primary purpose of this study was to assess the attitudes, experiences, and awareness level of students exposed to a specialized transportation curriculum and to track the progress of participants in a series of summer transportation institutes and other outreach programs held during the period, 1999-2008.  These programs include the Summer Transportation Institutes in Texas, Go Girl!, On the Move!, Career Exploration, the Rural Transportation Institutes, and Students from Nontraditional Backgrounds.   Although an attempt was made to contact students from all of outreach events, the vast majority of responses and data were obtained from the participants in the Texas Summer Transportation Institute and the SWUTC funded Summer Aviation Transportation Institute and Rural Summer Transportation Institute.

Many of the students contacted are either currently attending a university or beginning their careers.  This project attempted to determine the status of these students and document whether and where they are attending college as well as their course of study. If appropriate the team then contacted the student to gauge their desire for interaction with either a University Transportation Center or transportation program.

Keywords: Careers in Transportation, Careers in Engineering, STEM, Transportation Outreach Programs

ENTIRE REPORT (Adobe Acrobat File – 233 KB)

Valuing Real Estate Externality-Based Option in Development of Transit System Projects

Xue Zhou and Ivan D. Damnjanovic, Texas A&M University, March 2010, 37 pp. (169112-1)

Capital-intensive transit projects rely on strong public support and availability of funds. While the general public has become a strong advocate for transit systems, budget shortfalls and financial constraints are still resulting in delays in project delivery. In such business environment, the public sector has an opportunity to partner with the private sector to deliver and operate needed infrastructures. In public-private arrangements, the private sector typically is unwilling to accept the system ridership risk, making such projects financially unfeasible. However, transit projects undoubtedly create value that is not internalized by the developer. The completion of a transit system not only increases the values of properties in the affected area, but also brings incremental tax revenue to the public sector. Thus, some of this newly created value can be shared with the private sector to make the project financially feasible. The objective of this paper is to develop a method for designing externality-based option and a model for its valuation. The proposed valuation model is based on the concept of auctions, where the price-jump results from the introduction of the new transit system. The numerical example results show that externality-based option could reduce private sector risk and add value to the private developer, making transit project more attractive.

 

Keywords: Externality, Tax-Increment, Real Estate, Contingent Claim Analysis, Pricing

ENTIRE REPORT (Adobe Acrobat File – 476 KB)

Quantifying Travel Time Variability in Transportation Networks

Stephen D. Boyles, Avinash Voruganti and S. Travis Waller, University of Texas at Austin, March 2010, 39 pp. (167275-1)

Nonrecurring congestion creates significant delay on freeways in urban areas, lending importance to the study of facility reliability.  In locations where traffic detectors record and archive data, approximate probability distributions for travel speed or other quantities of interest can be determined from historical data; however, the coverage of detectors is not always complete, and many regions have not deployed such infrastructure.  This report describes procedures for estimating such distributions in the absence of this data, considering both supply-side factors (reductions in capacity due to events such as incidents or poor weather) and demand-side factors (such as daily variation in travel activity).  Two demonstrations are provided: using data from the Dallas metropolitan area, probability distributions fitting observed speed data are identified, and regression models developed for estimating their parameters.  Using data from the Seattle metropolitan area, the appropriate capacity reduction applied to planning delay functions in the case of an incident is identified.

 

Keywords: Transportation Planning, Regression Models, Supply-Side Analysis, Demand-Side Analysis, Travel Demand, Travel Speed Distribution

ENTIRE REPORT (Adobe Acrobat File – 592 KB)

A Statistical Analysis of the Relationship Between Land Values and Freestanding Bus Facilities

Carol Lewis, and Gwen Goodwin, Texas Southern University, February 2010, 26 pp. (167372-1)

Public transit professionals continue to seek methods that offer greater service opportunities, while not materially increasing the costs of service provision.  One strategy is to construct bus transit centers which operate much like the airline hub and spoke concept.  More frequent destinations can be made available with shorter patron wait times and minimal to no increase in the number of bus hours.  Patrons tend to appreciate the convenience of a transfer occurring in a lighted facility, in addition to the increased level of bus service.  In many cases, there is an anticipation of higher density residential near these areas.  A number of the bus based centers may be close to single family neighborhoods.  Residents might express concerns about the value of their property given the presence of a bus transit center near their home.  Besides the bus transit centers that serve traditional local or express routes, a number of cities are planning bus rapid transit lines with stations that might lead nearby communities to ask similar questions about property values.  This study assesses the effect of bus transit centers in Houston, Texas, on nearby single family residential property values.

Keywords: Land Values, Transit Centers, Bus Facilities, Property Values

ENTIRE REPORT (Adobe Acrobat File – 215 KB)

Addressing Safety Through Evaluation and Optimization of Permeable Friction Course Mixtures

Allex E. Alvarez, Amy Epps Martin and Cindy K. Estakhri, Texas A&M University, January 2010, 91 pp. (476660-00013-1)

Permeable friction course (PFC) mixtures are a special type of hot mix asphalt characterized by a high total air voids content to guarantee proper functionality and stone-on-stone contact of the coarse aggregate fraction to ensure adequate mixture stability. Thus, PFC mixtures constructed in a thin layer at the surface of a pavement structure produce several benefits in terms of economy, safety, and the environment. This project focused on the analysis of functionality (i.e., drainability), stone-on-stone contact, and mixture internal structure to propose improvements in these three aspects for PFC mix design and evaluation. The analysis was based on both a macroscopic assessment of mixture properties and a study of internal structure using X-ray Computed Tomography (X-ray CT) and image analysis techniques.

The assessment of drainability led to a recommendation to use the expected value of permeability (based on a modified Kozeny-Carman equation) for analytical prediction of permeability. The water-accessible AV content was also proposed as a surrogate of the total AV content for indirect assessment of permeability. In addition, field drainability of PFC mixtures can be evaluated in terms of the water flow value (outflow time). Proposed enhancements for the quantitative determination of stone-on-stone contact were established using the Discrete Element Method and image analysis techniques. This analysis allowed recommendation of: (i) a criterion to determine the breaking-sieve size (sieve size differentiating the coarse and fine aggregate fractions) and (ii) verification of stone-on-stone contact using a maximum voids in coarse aggregate (VCA) ratio of 0.9 over the current criterion (VCA=1.0). The analysis of mixture internal structure led to recommend reduction of the horizontal heterogeneity of total AV content by using road cores with a minimum 152.4 mm diameter and coring SGC specimens from 152.4 to 101.6 mm in diameter. In addition, limitations in comparing the vertical distribution of AV of field- and laboratory-compacted mixtures supported recommendation of field-compaction control and future analysis of mixtures produced accordingly.

Keywords: Permeable Friction Course, Open-Graded Friction Course, Permeability, Stone-on-Stone Contact, Mixture Internal Structure, X-ray Computed Tomography, Image Analysis, Total Air Voids Content

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Developing and Applying Mobility Performance Measures for Freight Transportation in Urban Areas

David Winterich, William L. Eisele, Juan Villa, and David L. Schrank, Texas A&M University, December 2009, 58 pp. (476660-00014-1)

This report summarizes the activities performed in a one-year study with the objective to develop an understanding of the interrelationships of urban goods movement and congestion and identify performance measures that will help evaluate the impact of goods movement in the urban area. Through a survey instrument and state-of-the-practice review, this research project investigated the impacts and interactions of commodity movements within an urban area, given traffic congestion.

Researchers generally found that traditional mobility monitoring performance measures (e.g., delay, travel time index) can be adopted for freight-related mobility performance measurement. From the surveys conducted, and the state-of-the-practice review, researchers also found that 1) recurring congestion (and most typical incident congestion) is a problem that carriers/shippers can plan for, and in most cases, they can deal with congestion as it comes along; and 2) carriers/shippers tend to estimate a time cushion (buffer) into their schedules to meet their delivery times. There are times when urban congestion levels can impact freight operations (e.g., just-in-time [JIT] deliveries for manufacturing, less-than-truckload [LTL] trips by truck). Researchers also documented the interrelationship of how decisions by either the public sector or the trucking companies can influence one another.

The results of this research will be valuable to decision-making staff at metropolitan planning organizations (MPOs) and local transportation organizations to understand the big picture of local truck movements, as well as performance measures that will assist public transportation agency staff in considering freight movements and impacts in project prioritization and selection.

Keywords: Urban Freight Movements, Performance Measures, Mobility Monitoring, Congestion, Freight Impacts, Delay

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

An Evaluation of Alternative Fuels Usage by Public Transit Agencies

Gwen Goodwin and Ronald Goodwin, Texas Southern University, December 2009, 60 pp. (167321-1)

The oil crisis of the 1970s forced Americans to reconsider using fossil fuels as a primary energy source. In the public transit arena, private transit companies found themselves unable to compete in the urban environment as rapidly rising oil prices negatively affected the economy and personal mobility. In response to the growing energy crises, the American government initiated policies designed to reduce the dependence on foreign oil. These new policies were implemented to reduce pollution, maintain fuel efficiency, and develop alternative fuels for use by private auto owners, governmental entities, and transit companies. This study offers a historical examination of the key legislation passed during the period of the 1970s – 2000s, provides a discussion of the types of alternative fuels developed and examines how transit agencies applied those technologies to try to meet the spirit of the legislation.

 

Keywords: Alternative Fuels, Transit Agency Alternative Fuel Use, Alternative Fuel Legislation

ENTIRE REPORT (Adobe Acrobat File – 383 KB)

Trip Internalization and Mixed-Use Development: A Case Study of Austin Texas

Ming Zhang, Alexander Kone, Shaun Tooley, and Ryan Ramphul, University of Texas at Austin, December 2009, 123 pp. (169207-1)

The Capital Area Metropolitan Planning Organization (CAMPO) in the Austin, TX region is incorporating a new regional growth concept, the Activity Centers for its Long-Range Transportation Plan. The planned Activity Centers would present such features as mixed uses, medium to high densities, and pedestrian-friendly environmental design, which are expected to influence travel. This study reports the needed local empirical evidence of trip making behavior in association with the Activity Centers’ attributes. From telephone interviews of local planners and work sessions with experts, the study identifies 42 mixed-use districts (MXDs) in the Austin area. In GIS, urban form indicators are derived for the MXDs and trip records from the 2005 Austin Activity Travel Survey are geocoded. The following analyses are then carried out for the MXD related travel: trip length distribution, trip generation rates and internal rate of capture, person miles of travel, vehicle ownership, departure time, and travel mode choice. With the empirical results, CAMPO models can be modified or refined to capture the potential effects of the Activity Centers growth strategy on regional travel.

Keywords: Activity Centers, Mixed-Use Development, Trip Generation, Travel Mode Choice, Austin, TX

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Intelligent Transportation Systems Data Compression Using Wavelet Decomposition Technique

Fengxiang Qiao, Hao Liu and Lei Yu, Texas Southern University, December 2009, 82 pp. (167651-1)

Intelligent Transportation Systems (ITS) generates massive amounts of traffic data, which posts challenges for data storage, transmission and retrieval. Data compression and reconstruction technique plays an important role in ITS data procession. Traditional compression methods have been utilized in Transportation Management Centers (TMCs), but the data redundancy and compression efficiency problems remain. In this report, the wavelet incorporated ITS data compression method is initiated. The proposed method not only makes use of the conventional compression techniques but, in addition, incorporates the one-dimensional discrete wavelet compression approach. Since the desired wavelet compression is a lossy algorithm, the balancing between the compression ratio and the signal distortion is exceedingly important. During the compression process, the determination of the threshold is the key issue that affects both the compression ratio and the signal distortion. An algorithm is proposed that can properly select the threshold by balancing the two contradicted aspects. Three performance indexes are constructed and the relationships between the three indices and the threshold are identified in the algorithm. A MATLAB program with the name Wavelet Compression for ITS Data (WCID) has been developed to facilitate the compression tests. A case study on TransGuide ITS data was put into play and a final compression ratio of less than one percent on the trade-off threshold value shows that the proposed approach is practical. Finally, the threshold selection algorithm can be further tuned up utilizing Autoregressive model so that the quality of reconstructed data can be improved with a minor overhead of saving only a few parameters.

Keywords: ITS Data Compression, Wavelet Decomposition, Signal Distortion; Compression Ratio, Threshold Selection, Autoregressive Model.

ENTIRE REPORT (Adobe Acrobat File – 1.2 MB)

Evolution of the Household Vehicle Fleet: Anticipating Fleet Composition, Plug-In Hybrid Electric Vehicle (PHEV) Adoption and Greenhouse Gas (GHG) Emissions in Austin, Texas

Sashank Musti and Kara M. Kockelman, University of Texas at Austin, December 2009, 165 pp. (169202-1)

Automobile ownership plays an important role in determining vehicle use, emissions, fuel consumption, congestion and traffic safety. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin’s household-fleet evolution. Results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are vehicle purchase price, type/class, and fuel economy (with 30%, 21% and 19% of respondents placing these in their top three). Most (56%) respondents also indicated that they would seriously consider purchasing a Plug-In Hybrid Electric Vehicle (PHEV) if it were to cost $6,000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle’s emissions, more strongly than they respond to information on fuel cost savings. 25-year simulations suggest that 19% of Austin’s vehicle fleet could be comprised of Hybrid Electric Vehicles (HEVs) and PHEVs under adoption of a feebate policy (along with PHEV availability in Year 1 of the simulation, and current gas prices throughout). In comparison to the base year (2009) total VMT, year 2034 vehicle miles traveled (VMT) levels are predicted to increase 154% by year 2034 in the TREND scenario. Total CO2 emissions fall by 22% in the PRICING scenario relative to the TREND scenario.

Keywords: Vehicle choice, Fleet Evolution, Vehicle Ownership, Plug-In Hybrid Electric Vehicles (PHEVs), Climate Change Policy, Stated Preference, Opinion Survey, Microsimulation

ENTIRE REPORT (Adobe Acrobat File – 1.1 MB)

Dynamic Traffic Assignment Based Trailblazing Guide Signing for Major Traffic Generator

Fengxiang Qiao, Yan Zeng and Lei Yu, Texas Southern University, November 2009, 41 pp. (476660-00046-1)

The placement of guide signs and the display of dynamic massage signs greatly affect drivers’ understanding of the network and therefore their route choices. Most existing dynamic traffic assignment models assume that drivers heading to a Major Traffic Generator (MTG) have sufficient knowledge of roadway networks. In this report, the concept of recognition level is defined to categorize drivers based on their unfamiliarity of the network and of the alternative routes between origins and destinations. Each catalog is assigned a specific utility function that is dependent on travel time, length of route and recognition parameters. Drivers’ route choice behavior is determined by these specific utility functions. A sample network is first employed to test the feasibility of the proposed model, and the result complies with the specified travel patterns. After that, a real network near Downtown Houston is used to further test the proposed model. An experiment is conducted based on the information collected from an on-site survey and the on-line real-time traffic map from Houston TranStar. In order to validate the necessity of the proposed model, a control experiment is carried out with all parameters being set in the same way as the designed experiment except that drivers are assumed to be fully familiar with the network layout and alternative routes. Test results show that the proposed model can fit the real case very well. The developed algorithm and the assessment procedure results are not only awfully imperative in trailblazing guide signing for MTGs, but also indispensable in both the modern Route Guidance System (RGS) and the Advanced Traveler Information System (ATIS), which are important components of the Intelligent Transportation System (ITS).

Keywords: Traveler Information and Guidance, Dynamic Traffic Assignment, Traveler Services Information, Guide Signing, Simulation and Modeling

ENTIRE REPORT (Adobe Acrobat File – 829 KB)

Compendium of Student Papers: 2009 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, October 2009, 106 pp. (476660-00003-2)

This report is a compilation of research papers written by students participating in the 2009 Undergraduate Transportation Scholars Program.  The ten-week summer program, now in its nineteenth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects.  The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) appropriate time-to-clear values for use in developing left-turn lane warrants; 2) driver behavior at freeway interchanges with horizontal signing; 3) quality assurance in speed data collection methods at high speeds; and 4) measuring traveler’s willingness-to-pay for time savings.
Keywords: Time-to-Clear, Left-Turn Lane; Driver Behavior; Freeway Interchanges; Horizontal Signing; Quality Assurance; Speed-Data Collection Methods; High-Speed; Traveler’s Willingness-to-Pay; Time Savings

ENTIRE REPORT (Adobe Acrobat File – 15.3 MB)

Multimodal Network Models for Robust Transportation Systems

Jennifer Duthie, Erin Ferguson, Avinash Unnikrishnan and S. Travis Waller, University of Texas at Austin, October 2009, 67 pp. (167867-1)

Since transportation infrastructure projects have a lifetime of many decades, project developers must consider not only the current demand for the project but also the future demand.  Future demand is of course uncertain and should be treated as such during project design.  Previous research for Southwest Region University Transportation Center (Report 167556) explored the impact of uncertainty on roadway improvements and found neglecting uncertainty to lead to suboptimal network design decisions. This research is extended in the current work by considering not only motor vehicle traffic, but other modes as well.

The first half of this report examines the problem of network flexibility in the face of uncertainty when constructing a potentially revenue-generating toll road project.  Demand uncertainty and network design are considered by way of a bilevel stochastic recourse model. The results from a test network, for which a closed form solution is possible, indicate that the value of network flexibility directly depends on initial network conditions, variance in future travel demand, and toll pricing decisions.

The second half of this report integrates Environmental Justice into the transit frequency-setting problem while considering uncertainty in travel demand from protected populations.  The overarching purpose is to improve access via transit to basic amenities to: 1) reduce the disproportionate burden transit dependent populations’ experience; and 2) increase the financial security of low-income households by giving them a feasible option to reduce their dependence on autos.  The example application illustrates the formulation successfully increases access to employment opportunities for residents in areas with the high percentages of low-income persons, as well as demonstrates the importance of considering uncertainty in the locations of low-income populations and employment.

Keywords: Transportation Network Flexibility, Travel Demand Uncertainty, Transportation Network Models, Transit Dependent Populations, Multimodal Network Models

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Pilot Information System for Cross-Border Hazmat Transportation

Rajat Rajbhandari, Ivan Calzada, Barry Thatcher, Michael Noonchester, Texas A&M University, October 2009, 101 pp. (476660-00016-1)

Under NAFTA requirements, all hazardous materials that are shipped into Mexico or generated during the manufacturing process must be shipped back to its point of origin, typically the United States.  Thus, the delivery and return of hazardous materials have created a hazmat transportation corridor. At present, there is no automated, real-time method to track hazardous materials shipments crossing the U.S.-Mexico border. As a result, border agencies (specially the first responders) do not have advanced information about the hazardous materials being transported through border crossings and other locations within their communities. This lack of information hinders first responder’s ability to respond to hazardous materials incidences.

The objective of the study was to propose a prototype of an information system by which hazardous materials movement will be relayed and/or shared with local and regional agencies (mainly the first responders) which will assist these agencies to respond to major hazardous materials incidents more efficiently. This prototype information system was designed for first responders as a model for what could be developed for the wide range of stakeholders from all U.S. and Mexican border states. A large part of the initial research was spent in identifying the agencies that played minor and major roles in transportation of hazardous materials across the border. The researchers found that a large number of agencies played various roles in what turned out to be extremely complicated process of hazardous materials transportation and incident response. Finally, based on stakeholder needs, the research proposed logical and physical architecture of a prototype system to monitor movement of hazardous materials in the border area and to provide advanced warning of hazardous materials related incidents to the first responders.
Keywords: Hazardous Materials, Border Crossing, Intelligent Transportation System

ENTIRE REPORT (Adobe Acrobat File – 4 MB)

Driver Eye-scanning Behavior at Intersections at Night

Laura L. Higgins, Myunghoon Ko, and Susan T. Chrylser, Texas A&M University, October 2009, 59 pp. (169111-1)

This research project analyzed drivers’ eye scanning behavior at night when approaching signalized and unsignalized intersections using the data from a head-mounted eye-tracking system during open road driving on a prescribed route.  During the 1000-ft approaching the intersections, drivers shifted their glance more frequently when approaching the signalized intersections than they did at unsignalized intersections.  Among different turning movements, left turns overall seemed to elicit different eye movement patterns than the right-turn or through-movements.  When approaching intersections where they would turn left, the drivers glanced most often straight ahead, while glances to the right side decreased in frequency and glances to the left increased in frequency compared to the right-turn and through-movement intersections.  This study used a binary logistic regression model to analyze the changes of probabilities of glances to each of four areas of the scene as a function of distance to the intersections.  At some intersections, the probabilities of glances at particular areas significantly changed with the distance to the intersection.   The report also discusses methodological issues with on-road studies, the coding of eye-tracker data, and problems with eye-tracking equipment.

 

Keywords: Driver Behavior, Eye Movement, Turning Movement

ENTIRE REPORT (Adobe Acrobat File – 1.4 MB)

Extreme Makeover: Using Technology and Social Networks for Outreach and to Update Existing Transportation Modules

Debbie Jasek, Texas A&M University, October 2010, 19 pp. (476660-00020-1)

In the past SWUTC has funded numerous projects for transportation outreach for K-12. These projects included: the Transportation Road Show (2002), Careers in Transportation (2003), the Rural Transportation Institute (2004), and Transportation Engineering Education and Outreach Pilot Program Targeting Students in Grades K-12 (1999).  Over the past 11 years these modules and presentations have been viewed by over 15,000 students. Some modules are still currently being used by outreach personnel. However, many of the modules are outdated and desperately in needed a makeover in order to make them relevant for today’s student audiences.

Technology and the technological IQ of the target audience have changed tremendously in the past 11 years. Today’s students surf the web, communicate through Facebook and MySpace, and they also communicate through Twitter and websites such as Squidoo.  Many students read blogs on a daily basis, the way older generations read newspapers. Interfacing with students through media that they use on a constant basis will cast a wider net to reach a diverse population of students.  This project forms a basis for future outreach projects, by updating previously developed materials, creating a new portal website that can be used for outreach and blogging, as well as the creation of Facebook transportation outreach groups for students.

Keywords: Careers in Transportation, Careers in Engineering, STEM, Transportation Outreach Programs

ENTIRE REPORT (Adobe Acrobat File – 168 KB)

Bush School Capstone Course Support: The Regional Impact of Climate Change on Transportation Infrastructure and Decision Making

Eric Lindquist, Texas A&M University, September 2009, 64 pp. (476660-00010-1)

The Master of Public Service and Administration program at Texas A&M’s Bush School of Government and Public Service requires that all second year graduate students participate in a two semester Capstone course. These courses represent the practical culmination of the degree program and are based on a real world research experience. For the 2008-09 school year, one of these Capstone efforts focused on the significant impact climate change will have on infrastructure and decision making in the Houston-Galveston area. Attention has recently shifted from the impact of transportation on climate to a focus on adaptation to potential climate stressors of sea level rise, increased frequency and magnitude of storms and severe weather events, and changes in precipitation and temperature. The Houston-Galveston Area Council (H-GAC) recognized this situation and agreed to support a Capstone class and project focusing on these issues. The Capstone report is included in this SWUTC report as Appendix A.

 

Keywords: Climate Change Adaptation, Climate Change and Transportation, Climate Change and Houston, TX

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

Vehicle and Driver Scheduling for Public Transit

Kristen Torrance, Ashley R. Haire and Randy B. Machemehl, University of Texas at Austin, August 2009, 44 pp. (476660-00063-1)

The problem of driver scheduling involves the construction of a legal set of shifts, including allowance of overtime, which cover the blocks in a particular vehicle schedule. A shift is the work scheduled to be performed by a driver in one day, while a block is a sequence of trips made by a single bus. Blocks can be divided between different drivers if they begin or end at relief points, providing the opportunity for change. The goal is to make the schedule as efficient as possible, therefore minimizing the amount of changes that need to be made.

In determining the ideal schedule, local and national labor rules must be considered. These involve restrictions specified by the user, including, but not limited to, total time worked per day; total time worked per week; the length of time that may be worked without a meal break; the total spreadover, which is the duration between beginning and ending a shift; and/or the number of days off per week (Wren and Rousseau, 1995).

The problem of vehicle scheduling involves determining the optimal route structure, span of service, and service frequencies for the transit agency and assigning vehicles to the routes. This involves considering cycle times, number of vehicles, timed transfers, layover time and locations, recovery time, and any difference in weekday and weekend services (Wren and Rousseau, 1995). Knowing the blocks of work that must be satisfied, vehicles must be assigned to each of the blocks and given departure and arrival times with a goal of optimizing the number of hours the vehicle is transporting passengers, known as platform hours.

The research contained herein describes work undertaken by the research team, including literature review and a survey of existing methodologies. Preliminary programming code was created to act as a benchmark for future endeavors in this area and elaboration of the complicating factors led the team to conclude that in order to fully complete a comprehensive working scheduling technique, substantially greater resources would be needed.

Keywords: Driver Scheduling, Vehicle Scheduling, Optimal Route Structure, Transit Platform Hours

ENTIRE REPORT (Adobe Acrobat File – 255 KB)

Sustainable Intersection Control to Accommodate Urban Freight Mobility

Bruce X. Wang and Kai Yin, Texas A&M University, August 2009, 54 pp. (476660-00015-1)

In this research, we studied green extension of a two-phased vehicle−actuated signal at an isolated intersection between two one-way streets. The green phase is extended by a preset time interval, referred to as critical gap, from the time of a vehicle arrival. The green phase switches if there is no arrival during the critical gap. We developed a model following a Poisson process that studied the intersection performance of traffic. We extended the model to cover the case of general traffic. Additionally, we derived system performance measures. Our findings show that our model is fairly flexible in accommodating freight traffic, and our model in the general case is asymptotically accurate under heavy traffic. Numerical tests show that the presence of critical gaps increases vehicle delay in most cases. This finding is enlightening regarding current practices.

 

Keywords: Intersection Control; Signal Timing; Actuated Signal System

ENTIRE REPORT (Adobe Acrobat File – 695 KB)

Network-based Decision Support Tool for Toll Roads, Ivan Damnjanovic

S. Travis Waller, Nevena Vajdic, David R. Suescun, Texas A&M University, August 2009, 109 pp. (0-5881-1)

Development, delivery, and operation of public infrastructure are becoming increasingly dependent on participation of the private sector. While revenue generating projects, such as toll roads, were traditionally developed and funded from the public sources, in recent years, as the public demand for new projects have exceeded the ability of the public sector to deliver them, the private investors have started to fulfill the gap between the needed and the available infrastructure.

The objective of this research was to develop a network-based method that allows an assessment of the effect of the public sector’s decisions regarding network improvements on the financial value of toll road projects.

 

Keywords: Toll Roads, Network Improvements, Feeder and Competing Links and Routes, Financial Feasibility

ENTIRE REPORT (Adobe Acrobat File – 734 KB)

A Methodology for Incorporating Fuel Price Impacts into Short-term Transit Ridership Forecasts

Ashley R. Haire and Randy B. Machemehl, University of Texas at Austin, August 2009, 147 pp. (169203-1)

Anticipating changes to public transportation ridership demand is important to planning for and meeting service goals and maintaining system viability. These changes may occur in the short- or long-term; extensive academic work has focused on bettering long-term forecasting procedures while improvements to short-term forecasting techniques have not received significant academic attention. This dissertation combines traditional forecasting approaches with multivariate regression to develop a transferable short-term public transportation ridership forecasting model that incorporates fuel price as a prediction parameter. The research herein addresses 254 US transit systems from bus, light rail, heavy rail, and commuter rail modes, and uses complementary methods to account for seasonal and non-seasonal ridership fluctuations. Models were built and calibrated using monthly data from 2002 to 2007 and validated using a six-month dataset from early 2008. Using variable transformations, classical data decomposition techniques, multivariate regression, and a variety of forecasting model validation measures, this work establishes a benchmark for future research into transferable transit ridership forecasting model improvements that may aid public transportation system planners in an era when, due to fuel price concerns, global warming and green initiatives, and other impetuses, transit use is seeing a resurgence in popularity.

Keywords: Ridership Forecasting, Transit Ridership, Public Transportation Ridership, Time Series Analysis, Fuel Price Effects

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Improving the Sustainability of Asphalt Pavements through Developing a Predictive Model with Fundamental Material Properties

Rashid K. Abu Al-Rub, Eyad A. Masad, and Chien-Wei Huang, Texas A&M University, August 2009, 59 pp. (476660-00007-1)

This study presents the numerical implementation and validation of general constitutive relationships for describing the nonlinear behavior of asphalt concrete mixes.  These constitutive relationships incorporate nonlinear viscoelasticity and viscoplasticity to predict the recoverable and irrecoverable responses, respectively.  The nonlinear viscoelastic deformation is modeled using Schapery’s model; while the irrecoverable component is represented using Perzyna’s viscoplasticity theory with an extended Drucker-Prager yield surface and plastic potential that is modified to capture the distinction between the compressive and extension behavior of asphalt mixes. The nonlinear viscoelastic and viscoplastic model is represented in a numerical formulation and implemented in a finite element (FE) code using a recursive-iterative algorithm for nonlinear viscoelasticity and the radial return algorithm for viscoplasticity. Then, the model is used to analyze the nonlinear viscoelastic and viscoplastic behavior of asphalt mixtures subjected to single creep recovery tests at different stress levels and temperatures. This experimental analysis includes the separation of the viscoelastic and viscoplastic strain components. Based on this separation, a systematic procedure is presented for the identification of the material parameters associated with the nonlinear viscoelastic and viscoplastic constitutive equations.  Finally, the model is applied and verified against a set of creep-recovery tests on hot mix asphalt at different stress levels and temperatures.

Keywords: Mechanistic Model; Viscoelasticity; Viscoplasticity; Damage Mechanics; Hot Mix Asphalt; Finite Element; Creep-Recovery

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Laboratory Investigation of a Novel Method to Accelerate Healing in Asphalt Mixtures Using Thermal Treatment

Amit Bhasin, Atul Narayan, and Dallas N. Little, Texas A&M University, August 2009, 35 pp. (476660-00005-1)

Asphalt binders have an inherent ability to reverse damage in the form of micro-cracks that is caused due to the repeated action of external loads. This reversal occurs during rest periods between load cycles. The phenomenon of crack reversal is referred to as autogenous or self-healing. The main objective of this project was to apply established principles of healing to investigate a novel technique to accelerate reversal of accumulated micro-crack in asphalt mixtures. This technique was developed and evaluated using a laboratory scale set up. Laboratory tests were used to evaluate the impact of thermal treatment on the fatigue cracking life of asphalt mixtures. Results from this study indicate that for two out of the three different types of asphalt mixtures, intermittent application of the thermal treatment resulted in approximately 50% increase in the fatigue cracking life of the mixture.

Keywords: Asphalt Mixture, Fatigue Cracking, Self-Healing

ENTIRE REPORT (Adobe Acrobat File – 1.9 MB)

Graduate Course Development: Transportation Policy and Politics

Eric Lindquist, Texas A&M University, August 2009, 45 pp. (167176-1)

Transportation, public policy, and politics are inextricably linked and have been, in the United States, from at least 1956, with the birth of the federal highway system and the Interstate Highway Act, if not earlier. Much of the transportation system we enjoy today is paid for by public funds—which in and of itself invokes a political process. From the 1956 Act to the present day debate on the latest federal transportation reauthorization effort, the effort to solve the transportation problems in this country has been a political process. As this report was being drafted, for example, the future of the latest federal transportation reauthorization, originally scheduled for debate this spring and summer has been put on hold by the Obama Administration as a result of political maneuvering. It is anticipated that the formal reauthorization will be put off for 18 months, while the current authorization will be extended through temporary measures. In spite of these linkages there are few graduate level courses that systematically explore the dynamic interaction of transportation, policy, and politics. The objective of this project was to address this situation and assess the potential for such a course at Texas A&M University (TAMU). We conducted content analysis of existing course syllabi at other universities, implemented an internet survey, and found a significant level of interest in providing such a course. A draft syllabus is included, as are reference lists and summaries of similar courses being offered elsewhere.

Keywords: Transportation Policy, Transportation Politics, Transportation Education

SUMMARY REPORT (Adobe Acrobat File – 325 KB)

Examining the Relationship between Community Design and Crash Incidence

Eric Dumbaugh, Robert Rae and Douglas Wunneberger, Texas A&M University, July 2009, 60 pp. (167173-1)

This study seeks to understand how urban form—specifically land use and street network configurations—may influence the incidence of traffic-related crashes injuries and deaths. It begins with an historic overview of the safety concepts that directed community design practice during the 20th century and details how these design concepts transformed themselves into contemporary community design practice. It details the development of a database of crash incidence and urban form at the block group level for the City of San Antonio, the first such database of its kind. Data acquired from this database are then modeled using negative binomial regression models to determine how urban form may be associated with the incidence of traffic-related crashes, injuries, and deaths at the block group level. It finds that the presence of arterial thoroughfares, strip commercial uses, and big box stores are significantly related with increased crash risk, while the presence of more traditional, pedestrian-scaled retail configurations are associated with a reduction in crash incidence. The population density of a block group was similarly associated with a reduction in crash incidence. Intersections had a mixed effect, reducing fatal crashes, but at least in the case of 4-leg intersections, also increasing the incidence of total and injurious crashes. Based on these findings, this study discusses the implications for design practice and outlines three strategies for enhancing traffic safety through community design.

Keywords: Traffic Safety, Community Design, Urban Design, Planning, Land Use

SUMMARY REPORT (Adobe Acrobat File – 6.4 MB)

RFID Applications in Transportation Operation and Intelligent Transportation Systems (ITS)

Fengxiang Qiao, Lei Yu, Rong Zhang, Zhiyuan Chen, and Reza Fatholahzadeh, Texas Southern University, June 2009, 57 pp. (476660-00044-1)

Radio frequency identification (RFID) transmits the identity of an object or a person wirelessly. It is grouped under the broad category of automatic identification technologies with corresponding standards and established protocols. RFID is suitable for applications in different industries and has penetrated into several aspects of our lives. The versatile features and benefits of RFID technology have proven that RFID can be widely applied in the field of transportation to improve driving safety, reduce vehicle collisions, and even help reduce vehicle emissions. Generally speaking, the applications of RFID in transportation are still limited and are not scanned and summarized well. This paper aims to conduct an extensive literature review to identify the existing and potential applications of RFID and its research opportunities and needs in transportation. Existing applications in transportation fields have been identified such as safety, operation – including Intelligent Transportation System (ITS) and Vehicle Infrastructure Integration (VII), security, policy, etc. Obstacles that possibly frustrate the wide and in-depth applications of RFID in the transportation area are in the aspects of technology, cost, policy, and privacy. RFID is one of the most forceful technologies that will affect a variety of aspects in transportation including ITS. It is believed that RFID-based technologies can be extensively exploited to improve transportation safety and security, increase the efficiency of the transportation system, ultimately save costs, and, therefore, improve the quality of human lives.

Keywords: RFID, Radio Frequency Identification, Automatic Identification, Wireless Communication, Intelligent Transportation System, Transportation Applications

SUMMARY REPORT (Adobe Acrobat File – 483 KB)

Moving Toward Implementation: An Examination of the Organizational and Political Structures of Transit-Oriented Development

Sharon Moses, Carol Abel Lewis and Krystal Lastrape, Texas Southern University, June 2009, 66 pp. (473700-00050-1)

The research explores the costs and impacts of Transit Oriented Development (TOD) and addresses the rationale for designing transit-oriented neighborhoods.  It also documents the outcomes and the impacts of implementing such projects and examines the perspective of the TODs’ genesis, whether by a public agency, a developer or the community.  This assessment adds to the vast body of knowledge about TOD providing case studies of several sites around the United States.

Keywords: Transit Oriented Development, TOD, Smart Growth, Walkable Communities

ENTIRE REPORT (Adobe Acrobat File – 811 KB)

Vehicle Infrastructure Integration (VII) Based Road-Condition Warning System for Highway Collision Prevention

Yi Qi, Xin Chen, Lane Yang, Bin Wang and Lei Yu, Texas Southern University, May 2009, 83 pp. (476660-00043-1)

As a major ITS initiative, the Vehicle Infrastructure Integration (VII) program is to revolutionize transportation by creating an enabling communication infrastructure that will open up a wide range of safety applications.  The road-condition warning system is a unique application of VII technology, which is to provide drivers with real-time information about unexpected roadway conditions ahead, such as accidents, speed reduction zones, hazardous weather conditions, etc. The safety effectiveness of the VII-based warning systems needs to be investigated under various driving conditions. In this study, three different types of warning systems: Rural Highway Driver Warning System (RHDWS), Highway Lane Change Warning System (HLCWS) and Work Zone Driver Warning System (WZDWS), were designed and tested in the designed highway scenarios by driving simulator experiments. The experimental results show that all  three systems can reduce the crashes in the designed environment. According to the survey result, the system is easy for the driver and helpful to them in driving safely under various driving conditions. The results of this research will be helpful for the decision making on the application of VII technology.

Keywords: Vehicle Infrastructure Integration, Driver Warning System, Run-off-road (ROR) Collision, Highway Safety, Driving Simulator

ENTIRE REPORT (Adobe Acrobat File – 3 MB)

Microsimulation of Household and Firm Behaviors: Anticipation of Greenhouse Gas Emissions for Austin, Texas

Sumala Tirumalachetty and Kara M. Kockelman, University of Texas at Austin, May 2009, 129 pp. (167272-1)

Anthropogenic greenhouse gas (GHG) emissions can be attributed to household and firm travel and building decisions. This study demonstrates the development and application of a microsimulation model for household and firm evolution and location choices overtime, along with evolution of the light duty vehicle fleet, residential building stock and travel decisions of persons and businesses in Austin, Texas over a 25-year period (from 2005 to 2030). Year 2005 zonal-level population and address-level employment data for the Austin, Texas region, coupled with various other aggregate data sets, are used to simulate the evolution of individual households and firms over time and space. Simulation results suggest a nearly 130% increase in vehicle-miles traveled (VMT), as population increases. and nearly the same increase in GHG emissions under the business-as-usual scenario. Total GHG emissions from household energy consumption are predicted to increase nearly 86% over the 25-year forecast period in the base scenario, and around 70% in other scenarios.  In contrast, average energy demand per firm is predicted to increase by 57% over the 25-year forecast period, mainly due to a transition to larger firm sizes.

Keywords: Microsimulation, GHG Emissions, Land Use, Travel Demand, Austin, Texas

ENTIRE REPORT (Adobe Acrobat File – 2.1 MB)

Analysis of Texas Biofuel Supply Chains Originating in the United States and Brazil

Leigh B. Boske and James T. Woodward, University of Texas at Austin, May 2009, 94 pp. (169201-1)

This 2009 study, funded by the Southwest Region University Transportation Center, investigates competing ethanol supply chains terminating in the State of Texas.  Midwest corn ethanol and Brazilian sugarcane ethanol constitute two sources of the biofuel necessary for synthesis of the ten percent ethanol, ninety percent gasoline fuel blend, commonly referred to as E10.  The updated 2007 Renewable Fuel Standard passed by Congress and signed into law by President George W. Bush in December 2007, promotes national availability of E10.  As a follow up to the 2008 Bioenergy and Alternative Fuels Scoping Study, this report discusses the requisite equipment, time, and costs to transport ethanol to the Lone Star State from its Midwestern or Latin American sources.  Federal biofuels policy along with new transportation technology, such as pipeline movement of renewable fuels, will largely determine whether domestic or international ethanol is more economically competitive in six Texas fuel markets.  If Congress chose to repeal the $0.54 per gallon domestic ethanol offset tariff, sugarcane ethanol pipelined inland from the coast could be more competitively priced than the corn variety as far west as the El Paso metropolitan area.

 

Keywords: U.S.-Brazil Trade, Maritime Transportation, Supply Chains, Intermodal Transportation, Transportation Corridors, Bioenergy, Biofuels, Alternative Fuels, Economic Impacts, Transport of Alternative Fuels, Transportation Infrastructure

ENTIRE REPORT (Adobe Acrobat File – 4.2 MB)

Private Sector’s Role in Public School Facility Planning

Jennifer Bennett and Tracy McMillan, University of Texas at Austin, April 2009, 85 pp. (167263-1)

This report explores the role of private consultants in the school facility planning process. It focuses on such issues as school siting and local government and school district collaboration. As such, it seeks to demonstrate the importance of the school facility planning process and its significance in the community. The primary data for this report is in-depth interviews with a variety of school facility planning consultants. The questions asked in the interviews were broad and open-ended, and the data was studied qualitatively to determine similar experiences of all interview participants. The conclusion of this report presents key findings from the interviews, as well as from background information on the subject.

Keywords: School Facility Planning, School Sitings

ENTIRE REPORT (Adobe Acrobat File – 13 MB)

Developing Sustainable Transportation Performance Measures for TxDOT’s Strategic Plan: Technical Report

Tara Ramani, Josias Zietsman, William Eisele, Duane Rosa, Debbie Spillane and Brian Bochner, Texas A&M University, April 2009, 218 pp. (0-5541-1)

For this research project, sustainable transportation can be viewed as the provision of safe, effective, and efficient access and mobility into the future while considering economic, social, and environmental needs. This project developed a performance measurement-based sustainability evaluation methodology for the Texas Department of Transportation’s (TxDOT’s) strategic plan.

The research team defined a set of objectives and performance measures that addressed the five goals of TxDOT’s strategic plan as well as sustainable transportation concerns. Researchers used a multi-criteria decision-making methodology to evaluate, benchmark, and aggregate the performance measures into a set of “sustainability index” values. The methodology, applicable at the highway corridor level, was integrated into a user-friendly, spreadsheet-based analysis tool that provided the sustainability index values (for current and future scenarios) as an output for a particular corridor. The analysis tool was used to carry out several case studies. The methodology and tool developed were found to be useful to assess progress towards TxDOT’s strategic plan goals while also addressing sustainability issues. The results and findings could be used to compare relative sustainability of different corridors, or assess the corridors over a period of time.

Keywords: Performance Measures, Sustainability, TxDOT, Strategic Plan

ENTIRE REPORT (Adobe Acrobat File – 4.2 MB)

Design-Build Agreements: A Case Study Review of the Included Handover Requirements

Jolanda Prozzi, Alejandro Perez-Ordonez, and Jorge A. Prozzi, University of Texas at Austin, April 2009, 66 pp. (167866-1)

Road infrastructure is a key component of any region’s transportation system.  It allows unprecedented levels of mobility, accessibility, and economic growth.  On the other hand, the cost associated with inadequate road infrastructure can amount to billions of dollars.

In the U.S., the largest revenue source for the funding of transportation infrastructure is the federal and state fuel taxes.  These taxes were conceived in the 1950s as an indirect charge to recover the costs of vehicle travel on the U.S. highway system.  However, this tax has not increased with the inflation rate and given increasing maintenance and construction costs, and more fuel efficient vehicles, the vehicle per mile tax has become inadequate.  State budget shortfalls affect the ability to maintain existing facilities properly and may lead to delayed maintenance which in turn may reduce the lifespan of roads, bridges, ports, and other infrastructures.

 

Keywords: Road Infrastructure, Road Maintenance

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Toward a Green Campus: A Transportation Strategy for Texas A&M University

Mohamadreza Farzaneh, Jae Su Lee, Tara Ramani, Laura Higgins, and Josias Zietsman,Texas A&M University, March 2009, 133 pp. (167174-1)

This research study produces a recommended sustainable transportation implementation plan for Texas A&M University (TAMU) to enhance the environmental performance of its campus transportation system. To achieve the goal, this study followed a historical design approach using existing documents and materials, along with the knowledge gained from interviews with campus transportation services and from site visits to a selected sample of universities whose size characteristics are similar to TAMU and who have successfully implemented sustainable transportation strategies. A series of data collection efforts was also conducted to provide a general picture of parking usage and parking users at TAMU.

The recommended implementation plan consists of an organizational framework of a sustainable campus transportation system as well as a series of specific strategies addressing different elements of such a system. It is concluded that TAMU needs to shift its approach to campus transportation from the current practice of providing to an approach based on controlling single-occupancy vehicular traffic to campus and improving its alternative transportation options, such as walking, biking, and transit.

 

Keywords: Campus Transportation, Sustainable Transportation, Alternative Transportation

SUMMARY REPORT (Adobe Acrobat File – 4 MB)

The U.S.-Brazil-China Trade and Transportation Triangle: Implications for the Southwest Region

Leigh B. Boske and John C. Cuttino, University of Texas at Austin, March 2009, 130 pp. (167861-1)

The advent of globalization and more integrated international trade has placed increased demands on transportation infrastructure.  This report assesses the impacts of triangular trade between and among the United States, Brazil and China with an emphasis on the effects on the U.S. Southwest region.  Triangular trade is viewed through a trade corridor analysis of the three sets of bilateral trading relationships.  Special emphasis is given to the transportation services that delimit the capacity to carry out triangular trade with particular attention to the latest developments in services and schedules.  While international trade trend analysis may point to China’s explosive consumption of raw materials from the U.S. and Brazil, this report also signals the increasing Chinese presence in the U.S. and Brazil via outsourcing and industrialization, crowding out U.S. and Brazilian domestic industry, and inhibiting Brazilian competitiveness in the U.S.  Notwithstanding these trends, a counterflow or reverse globalization is also beginning to appear where Brazil and China are making investments in each other and the U.S. in order to secure their raw materials and access consumer markets.  Future analysis of transportation infrastructure demand in the U.S. Southwest region may need to be flexible to account for these developments, first visible through a trade corridor analysis of the movement of goods across complete supply chains.

Keywords: U.S.-China Trade, U.S.-Brazil Trade, China-Brazil Trade, Maritime Transportation, Supply Chains, Intermodal Transportation, Transportation Corridors

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Future Travel Demand and Its Implications for Transportation Infrastructure Investments in the Texas Triangle

Ming Zhang and Binbin Chen, University of Texas at Austin, March 2009, 50 pp. (167276-1)

This study takes a megaregion approach to project future travel demand and choice of transport modes in the Texas Triangle, which is encompassed by four major metropolitan areas, Dallas-Fort Worth, Houston, San Antonio, and Austin. The model was developed based on three behavioral characteristics of human travel. First, as income grows, demand for more and faster mobility increases. Second, on average, individuals allocate 1-1.5 hours per capita per day for travel. Third, people allocate 10-15% of per capita personal income for transportation related expenses.

Measured by person-kilometers of travel (PKT), the total mobility demand in the Triangle region is projected to grow nearly four times from 480 billion in year 2000 to 1.8 trillion in year 2050. Per capita PKT is expected to increase from 32,700 to 61,000 for the same time period. The projections show that more than 70% of the year 2050 travel demand likely comes from high-speed travel at 600 km per hour..The study results call for serious consideration of investing in high-speed travel in the form of High Speed Rail (HSP) now in order to accommodate the future travel demand in the Triangle Region.

Keywords: Travel Demand, Texas Triangle, Megaregion, High-speed Travel

ENTIRE REPORT (Adobe Acrobat File – 1.8 MB)

 

Transit Services for Sprawling Areas with Relatively Low Demand Density: A Pilot Study in the Texas Border’s Colonias

Luca Quadrifoglio, Shailesh Chandra and Chung-Wei Shen, Texas A&M University, February 2009, 86 pp. (167177-1)

The colonias along the Texas-Mexico border are one of the most rapidly growing areas in Texas. Because of the relatively low‑income of the residents and an inadequate availability of transportation services, the need for basic social activities for the colonias cannot be properly met. The objective of this study is a to have a better comprehension of the status quo of this communities, examine the potential demand for an improved transportation service as well as evaluate the capacity and optimum service time interval of a new demand responsive transit “feeder” service within one representative colonia, El Cenizo. We present a comprehensive analysis of the results of a survey conducted through a questionnaire to evaluate the existing travel patterns and the potential demand for a feeder service. The results from the subsequent simulation analysis showed that a single shuttle would be able to comfortably serve 150 passengers/day and that the optimal headway between consecutive departures from the terminal should be between 11-13 minutes for best service quality. This exploratory study should serve as a first step towards improving transportation services within these growing underprivileged communities, especially for those with demographics and geometry similar to our target area of El Cenizo.

 

Keywords: Flexible Transit, Demand Responsive, Insertion Heuristic, Saturation Point, Optimal Headway

SUMMARY REPORT (Adobe Acrobat File – 811 KB)

Computer Simulation-Based Framework for Transportation Evacuation

Fengxiang Qiao, Ruixin Ge and Lei Yu, Texas Southern University, January 2009, 117 pp. (473700-00057-1)

Since emergencies including both natural disasters and man-made incidents, are happening more and more frequently, evacuation, especially transportation evacuation, is becoming a hot research focus in recent years. Currently, transportation evacuation study focuses on evacuating people and property from large areas and does not address the problem of transportation evacuation in a small and dense area. This research is intended to identify the study framework of developing transportation evacuation plans in small and dense areas. Texas Medical Center (TMC), Houston, Texas, is selected as case study in this thesis. Incidents are assumed based on potential threats. Traffic information is collected through filed data collections in the TMC area, and evacuation scenarios with incidents and management improvements are coded and simulated in VISSIM, a microscopic traffic simulation model. Genetic Algorithm is one of the calibration methods for searching multiple parameters at the same time and is used in this thesis to calibrate parameters of driving behaviors in VISSIM by using field collected and simulation data. Based on the simulation results, potential improvements and measurement of effectiveness (MOE) of operations such as Reversed Lane (RL) and In-bound Shuttle (IS) are analyzed and evaluated. Simulation results show that the evacuation would be much more efficient if appropriate operational strategies are implemented. Proper management improvements such as Reversed Lane and In-bound Shuttle could greatly maximize the number of persons/vehicles evacuated in the area. The selected operational plan can efficiently evacuate all persons in the Texas Medical Center in suitable simulation scenario under a given incident assumption. The framework of developing transportation evacuation plan is tested and proven to be effective in the Texas Medical Center. The microscopic simulation based study process is targeted on small and dense areas and it can be used in any other similar areas. It is recommended that further work be conducted to form a comprehensive evacuation plan.

Keywords: Evacuation, Safety and Security, Chemical Spills, Terrorism, Simulation, Computer Science, Traffic Flow Theory, Highway Operations, Intelligent Transportation Systems, Geographic Information Systems, Global Positioning System, Transportation Planning, Traffic Engineering

ENTIRE REPORT (Adobe Acrobat File – 2 MB)

Protecting and Preserving Rail Corridors Against Encroachment of Incompatible Uses

Lisa Loftus-Otway, C. Michael Walton, Lynn Blais and Nathan Hutson, University of Texas at Austin, January 2009, 194 pp. (0-5546-1)

Rail Corridor preservation and planning for the purpose of reducing or restricting incompatible development is an area of growing importance. This report provides an overview regarding encroachment and the elements that contribute to potentially incompatible development along rail corridors. The report reviews the legal tools that currently exist within Texas for corridor preservation and provides recommendations for new legislation, including draft legislation. The report then reviews the state of practice of corridor planning and preservation with mitigation against encroachment both in Texas and in selected other states around the country. The report pays special attention to incidents in which rail corridors are envisioned to host both freight and passenger services and the implications on land use. Finally, the report provides a review of costs associated to deal with encroachment, whether by planning, preservation, collaboration, or mitigation.

Keywords: Corridor Preservation, Encroachment, Transit Oriented Development, Incompatible Land Use, Shared Track, Rail Relocation

ENTIRE REPORT (Adobe Acrobat File – 17.5 MB)

Addressing Cargo Security with Strategies Involving Private Sector

Jason R. West, C. Michael Walton and Alison J. Conway, University of Texas at Austin, December 2008, 38 pp. (473700-00095-1)

The public and private sectors contributing to goods movement agree that cargo security has not been addressed nearly as much as physical and vessel security.  Addressing cargo security will require additional operational data that is not currently used in public sector security analysis and decision making. The two strategies presented to acquire operational data are freight advisory councils and cargo data collection portals that have been developed by Horizon Services Group.  The report identifies four steps that freight advisory councils could implement to improve coordination for cargo security and provides an overview of the cargo data collection portal as envisioned by Horizon Services Group.

 

Keywords: Security, Cargo, Freight Transportation, Planning, Public-Private Partnerships

SUMMARY REPORT (Adobe Acrobat File – 341 KB)

Measuring the Marginal Cost of Congestion

Mark Burris and Sunil Patil, Texas A&M University, December 2008, 70 pp. (473700-00088-1)

This study attempted to estimate the effect of additional vehicles joining the traffic stream when it is near capacity. The study used data from highways I-35, I-45 in Texas and I-80 in California aggregated at different time intervals. Various macroscopic traffic flow models, Catastrophe model and the bottleneck model were studied in order to identify models that best represent the speed-flow relation for the traffic data over complete range of flow.

The Catastrophe model and the bottleneck model did not fit the data well, while three macroscopic models, the Modified HCM, Newell-Franklin and Van Aerde model were found to fit the data well. Using congestion pricing theory the optimum toll rates were calculated for each of these three models. The optimum toll rates were then compared with the toll rates on some of the existing variably priced toll roads the US. The optimum toll rates estimated using Modified HCM, Newell-Franklin and Van Aerde model were $0.65, $0.81 and $0.97 per mile assuming the value of travel time savings as $20/hr for the near capacity flow. These toll rates were found to be lower when compared with the maximum toll rates on three of the existing variable toll facilities which charge about $1/mile during the hours of extreme congestion.
Keywords: Marginal Cost of Congestion, Congestion Pricing, Traffic Flow Models, Catastrophe Theory

ENTIRE REPORT (Adobe Acrobat File – 981 KB)

A Review of Warm Mix Asphalt

Arif Chowdhury and Joe W. Button, Texas A&M University, December 2008, 75 pp. (473700-00080-1)

Warm Mix Asphalt (WMA) technology, recently developed in Europe, is gaining strong interest in the US.  By lowering the viscosity of asphalt binder and/or increasing the workability of mixture using minimal heat, WMA technology allows the mixing, transporting, and paving process at significantly lower temperature.  Using this new technology, asphalt mix can be produced as much as 100ºF lower than traditional hot mix asphalt (HMA). Several benefits of lower mixing and compaction temperature include: less emission, savings in energy cost, longer construction season, less odor, and construction during non-peak periods.  Despite the apparent benefits, some researchers are concerned about the long-term performance of this new mixture.  In last few years, dozens of field test sections have been constructed thorough out the USA using different WMA technologies.  It is too early to report the performance; but so far, no negative performance has been reported in the literature.  In the last few years, several large national and state level research projects have been initiated to evaluate, validate, and implement this new technology.

This report documents the results of a comprehensive review of worldwide information dealing with the following issues as related to warm mix asphalt:  Current state of the art/practice of WMA; cost and benefits of WMA technology; plant modifications to accommodate WMA; mixture design; durability and performance; performance related testing; quality control; specifications; and construction guidelines.

Keywords: Warm Mix Asphalt, Hot Mix Asphalt

ENTIRE REPORT (Adobe Acrobat File – 940 KB)

Loss Modeling for Pricing Catastrophic Bonds

Ivan Damnjanovic, John B. Mander and Jyotirmoy Sircar, Texas A&M University, December 2008, 80 pp. (167172-1)

In the research, a loss estimation framework is presented that directly relates seismic hazard to seismic response to damage and hence to losses. A Performance-Based Earthquake Engineering (PBEE) approach towards assessing the seismic vulnerability of structures relating an intensity measure (IM) to its associated engineering demand parameter (EDP) is used to define the demand model. An empirically calibrated tripartite loss model in the form of a power curve with upper and lower cut-offs is developed and used in conjunction with the previously defined demand model in order to estimate loss ratios. The loss model is calibrated and validated for different types of bridges and buildings. Loss ratios for various damage states take into account epistemic uncertainty as well as an effect for price surge following a major hazardous event. The loss model is then transformed to provide a composite seismic hazard-loss relationship which is used to estimate financial losses from expected structural losses.

The seismic hazard-loss model is then used to assess the expected spread, that is the interest rate deviation above the risk-free (prime) rate in order to price two types of CAT bonds: indemnity CAT bonds and parametric CAT bonds.

 

Keywords: Loss Modeling, Performance Based Earthquake Engineering, Catastrophic Bonds

SUMMARY REPORT (Adobe Acrobat File – 1.6 MB)

Who Uses Toll Roads? An Analysis of Central Texas Turnpike User

Chris Robertson, Jolanda Prozzi and C. Michael Walton, University of Texas at Austin, December 2008, 136 pp. (476660-00065-1)

The report characterizes with the greatest detail both the passenger and commuter users as well as non-users of the Central Texas Turnpike System recently opened in November 2006 in Austin, TX.  The process of analysis includes a review of literature of other tolling facilities in the nation, where focus is given on studies of similar nature regarding demographics of users both among passenger and commercial motorists.  This background study also touches on the general environmental justice impacts of tolling facilities.  The report continues by using survey data taken both prior to and after the construction of the turnpike system in regards to preference and usage by local residents.  The last portion of the report concerns the analysis of actual transaction data from the Central Texas Turnpike System – where transactions are linked to account type, axle count and billing zip code.  This actual data coupled with the stated preferences of the surveys provides a detailed look into the characteristics of a typical toll road user in the Central Texas area. These findings are presented and discussed in detail.

 

Keywords: Tolls, Toll Road, Tolling Facilities, User Fees, Environmental Justice

SUMMARY REPORT (Adobe Acrobat File – 8 MB)

An Assessment of Transit Ridership: Increased Suburban to Urban Public Transportation Options in Houston, Texas

Jamaal Schoby and Carol A. Lewis, Texas Southern University, November 2008, 90 pp. (473700-00053-1)

Suburban development is occurring near urban areas across America. Often these communities are separated by large masses of land with no linkage to the urban core. Referred to as urban sprawl, this type of development causes a challenge for transportation planners in providing adequate public transportation services to suburban communities.  This research applied a transit needs index to assess whether there might be demand for public transportation options between selected Houston suburban counties and the urban core.  The research found that several neighborhoods within three selected suburban counties received a high rating on the index and are good candidates for public transportation.

Keywords: Suburban Transit Need, Transit Need Index

ENTIRE REPORT (Adobe Acrobat File – 3.2 MB)

Analysis and Assessment of Microbial Biofilm-Mediated Concrete Deterioration

David Trejo, Paul de Figueiredo, Mauricio Sanchez, Carlos Gonzalez, Shiping Wei, and Lei Li, Texas A&M University, October 2008, 38 pp. (476660-00008-1)

Inspections of bridge substructures in Texas identified surface deterioration of reinforced concrete columns on bridges continuously exposed water.  Initial hypothesis were that the surface deterioration was a result of the acidity of the water in which the columns were exposed.  However, evaluation of the water acidity indicated that the surrounding waters were only very slightly acidic and near neutral.  Discussions between engineers from the Texas Department of Transportation (TxDOT) and researchers at Texas A&M University and the Texas Transportation Institute (TTI) hypothesized that the damage could be a result of microbial attack.  Microbial attack is often identified as an acid attack because some microbes can produce sulfuric acid.  This research investigated whether microbes were present at areas on the bridge that were exhibiting attack, determined if there was a correlation between degree of damage and number of microbes present, determined if these microbes were acid producing microbes, and identified the microbes present at the field sites.  Results indicate that microbes are present at the bridge columns experiencing surface deterioration, that the number of microbes present is directly correlated with the degree of damage, and that these microbes are acid producing.  The research identified five genera: these included Bacillus, Brachybacterium, Flavobacterium,Lysinibacillus and Thiomonas. The group with the largest numbers of representatives was Bacillus, which was composed of 17 strains.  The second largest group was identified as Thiomonas perometabolis, which consisted of seven strains.  The researchers concluded that the damage to the concrete bridge columns is microbial attack.  Because some bridge structures are exhibiting significant microbial attack of the concrete cover and because the long-term performance of the columns (and hence bridges) are most sensitive to concrete cover, further research is needed on how to prevent and mitigate this attack.

Keywords: Concrete, Microbes, Deterioration, Service Life, Bridge, Microbial Deterioration, Corrosion

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Transportation Infrastructure and Quality of Life for Disadvantage Populations: A Pilot Study of El Cenizo Colonia in Texas

Cecilia Giusti, Chanam Lee, Dominique Lord and Meghan Wieters, Texas A&M University, September 2008, 126 pp. (167162-1)

This research is a pilot study aimed to identify environmental characteristics in colonias that are related to infrastructure and safety, access to goods and services, and quality of life. A secondary objective consisted of evaluating a variety of tools that could be used to identify and assess these environmental characteristics. El Cenizo in Webb County, Texas, was selected as our study colonia after preliminary visits and investigations. A multi-disciplinary approach framed this study, considering the transportation, urban design and planning, public health, and socioeconomic dimensions as potential determinants of the residents’ mobility behaviors, environmental perception, and quality of life. Three instruments were developed to collect data for this research: 1) a survey, 2) an activity diary or travel diary, and 3) environmental audit instruments. Additionally, this study also included a small sub-group study testing the usability of wearable Global Positioning Systems (GPS) units as a research tool to capture spatial-behavioral data, combined with travel diary. First, the study has generated valuable data on transportation and mobility behaviors where almost no-information is available. Second, the multidisciplinary approach has allowed a comprehensive approach towards a better understanding of the current needs of colonias, especially those related to pedestrians. Some of them could be easily addressed with direct short-term interventions while other require a more long-term plans. Third, the assessment of new research tools offers useful insights for future research in the context of similar low-income marginalized communities.

Keywords: Colonia, Disadvantage Population, Health, Mobility, Walkability, Transportation, Built Environment, Safety, Transportation Infrastructure, Quality of Life, Economic Development, Latino/Hispanic, Minorities

ENTIRE REPORT (Adobe Acrobat File – 2.7 MB)

Characteristics of Drayage Operations at the Port of Houston

Robert Harrison, Nathan Hutson, Jason West and Julie Wilke, University of Texas at Austin, September 2008, 40 pp. (473700-00075-1)

Port drayage, defined as a container truck pickup to or from a seaport terminal with both the trip origin and destination in the same urban area, is a critical yet comparatively understudied link in the intermodal supply chain. Because port dray trucks operate primarily in urban environments, they can have a significant impact on congestion and air quality. The primary goal of this study is to identify key dray industry characteristics at the Port of Houston Authority (POHA) to help planners prepare for increasing container volumes while maintaining profitability and mitigating societal costs. The report gives the results of interviews with dray managers and a survey of 103 port drivers at the Port of Houston Barbours Cut container terminal on demographics, working conditions, truck characteristics, route characteristics and port operations. The results of the study are then compared against the existing literature, most of which comes from the Los Angeles area. Substantial variation is shown in the age and mileage of trucks. While only a minority of drivers was unsatisfied with overall terminal efficiency, many had suggestions on ways in which efficiency could be improved. The industry is found to be relatively stable despite the increasing demands placed by high container growth rates which have created a shortage of drivers at some locations. Lastly, the report examines methods in which the dray fleet could be modernized through air quality improvement grants.

Keywords: Drayage, Intermodal, Ports, Container Terminals, Dray Drivers

ENTIRE REPORT (Adobe Acrobat File – 316 KB)

A Comprehensive Assessment of Children’s Activity and Travel Patterns

Rachel B. Copperman and Chandra R. Bhat, University of Texas at Austin, September 2008, 104 pp. (167270-1)

This report provides a comprehensive review of previous research on children’s activity engagement and travel by focusing on the dimensions characterizing children’s activity-travel patterns and the factors affecting these dimensions.  In addition, an empirical analysis is undertaken of the post-school out-of-home activity-location engagement patterns of children aged 5 to 17 years.  Specifically, this research effort utilizes a multinomial logit model to analyze children’s post-school location patterns, and employs a multiple discrete-continuous extreme value (MDCEV) model to study the propensity of children to participate in, and allocate time to, multiple activity episode purpose-location types during the after-school period.  Finally, the paper identifies the need and opportunities for further research in the field of children’s travel behavior analysis.

Keywords: Children, Travel Behavior, Travel Demand Modeling, Time-Use

ENTIRE REPORT (Adobe Acrobat File – 776 KB)

Compendium of Student Papers: 2008 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, August 2008, 193 pp. (476660-00003-1)

This report is a compilation of research papers written by students participating in the 2008 Undergraduate Transportation Engineering Fellows Program.  The ten-week summer program, now in its eighteenth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects.  The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) selecting warning signs using decision theory and systems engineering concepts; 2) estimating corridor travel time from arterial traffic volume; 3) evaluating the effectiveness of life cycle variables in travel demand modeling;  4) estimating cross median crashes on horizontal curves; and 5) driver workload and visual studies.
Keywords: Warning Signs; Decision Theory and Systems Engineering Concepts; Corridor Travel Time; Traffic Volume; Life Cycle Variables; Travel Demand Modeling; Cross Median Crashes; Horizontal Curves; Driver Workload; Visual Studies

ENTIRE REPORT (Adobe Acrobat File – 1.8 MB)

On the Move! Exploring Transportation Career Horizons

Debbie Jasek, Texas A&M University, August 2008, 34 pp. (167164-1)

A recent Southwest University Transportation Center (SWUTC) project entitled Go! Girl! provided standing room only participation for the career workshops and activities it presented. The number of agencies, schools and universities offering support for the program and requesting a program in their area could not be accommodated in a the time frame of a one-year grant. The need for middle school programs that explore career activities became increasingly evident as the project progressed.

The concept for On the Move! originated from success of Go Girl!.  The team wanted to examine if the same type of program could be applied for both boys and girls and whether those activities would be received with the same enthusiasm.  The goal of On the Move! was to create one day events that encouraged students’ interest in STEM areas and transportation careers. It was also important that the event could be easily replicated for future use.

A total of eight separate events were piloted to diverse audiences across Texas. Each event created using a slightly different approach for sparking students’ interest in STEM. All of the events were produced at a cost of less than $1,000 and all of the events were well attended and well received.  A total of 1,175 students participated in the initial On the Move! outreach events and over 3,400 other students were reached through On the Move!  career fair and science night events.  Almost all of  these events have continued to be replicated through other funding sources.

Keywords: Careers in Transportation, Careers in Engineering, STEM, Transportation Outreach Programs

ENTIRE REPORT (Adobe Acrobat File – 274 KB)

Integration and Consolidation of Border Freight Transportation Data for Planning Applications and Characterization of NAFTA Truck Loads for Aiding in Transportation Infrastructure Management: Second Year

Jolanda Prozzi, Jorge Prozzi, Juan C. Villa, Dan Middleton, and Jeffery E. Warner, Texas A&M University, July 2008, 106 pp. (0-5339-2)

Average Daily Truck Traffic (ADTT) increased dramatically in Texas in the 1990s partly because of the implementation of the North American Free Trade Agreement (NAFTA).  Accurate information on truck volumes and truck characteristics is critical to transportation planning and infrastructure investments conducted by the Texas Department of Transportation (TxDOT) and other public agencies responsible for the road system in the State of Texas.  This report covers the second year activities of TxDOT Research Project 0-5339.  The objectives in the second year were to (a) collect data from a statistical sample of Mexican carriers – those that have applied to operate beyond the current commercial zones once the border opens – on the size of the Mexican companies, the types of operations, and equipment currently used and anticipated to be used for cross-border movements, and (b) to collect and analyze weigh-in-motion data from Texas and Mexico in order to establish their main characteristics as they affect pavement performance.

Keywords: Texas-Mexico Truck Data, Truck Border Crossing Data

ENTIRE REPORT (Adobe Acrobat File – 898 KB)

Developing Specifications for Performance-Based Maintenance Contracts

Ivan Damnjanovic, Seok Kim and Vighnesh P. Deshpande, Texas A&M University, June 2008, 82 pp. (167161-1)

Performance-based maintenance contracts are becoming increasingly popular method of procuring maintenance work.  This study presents a framework for specifying such contracts.  This framework is based on developing a pavement reliability model that is able to account for the effects of rehabilitation actions. The developed reliability model is able to predict the pavement performance before as well as after rehabilitation actions. Numerical illustration for optimization model shows that the developed model can be used to obtain an optimal trade-off between cost and performance. Further, the model considers a tradeoff between economies of scale associated with managing longer pavement sections, and risk mitigation benefits with managing relatively smaller e.g. more homogeneous sections. The results indicate that the length of optimal management sections depends not only on risk premium costs, but also the ability of the contractor to explore economies of scale. The model is illustrated using typical data available to transportation agencies.

Keywords: Performance-Based Maintenance Contract, Optimal Management Sections, Flexible Pavements, Rehabilitation, Reliability, Optimization

ENTIRE REPORT (Adobe Acrobat File – 1.9 MB)

Analysis of Federal and State Discretionary Funding of Highway and Transit Projects in FTA Region VI 1993-2000

Ronald Goodwin and Gwen Goodwin, Texas Southern University, June 2008, 32 pp. (167622-1)

The divestiture of the Federal Highway Trust Fund gave local officials the financial resources necessary to encourage the development of new transportation-related projects.  Under the auspices of the Intermodal Surface Transportation Efficiency Act (ISTEA), some of these projects included bikeways, alternatives fuels demonstration projects, and corridor beautification.  ISTEA was not designed to hinder highway development and research, but encourage the implementation of alternate mobility strategies, especially in the country’s urban cores. While ISTEA was the first attempt at discretionary funding, it was eventually replaced by the Transportation Efficiency Act for the 21 Century (TEA-21) and subsequently the Safe, Accountable, Flexible Efficient Transportation Equity Act- A Legacy for Users (SAFETEA-LU). Despite the efforts this legislation, most urban cores still seem dependent upon highways.

This study conducts an historical evaluation of federal and state discretionary funds from 1993 to 2000 to determine the distribution patterns in Region VI (Texas, Louisiana, New Mexico, Arkansas, and Oklahoma).

Keywords: ISTEA, TEA-21 Funding, Discretionary Funding of Highway and Transit Projects

ENTIRE REPORT (Adobe Acrobat File – 246 KB)

A Scoping Study of the Impacts of Bioenergy and Alternative Fuels on the Southwest Region’s Economy and Transportation Infrastructure

Leigh B. Boske and James T. Woodward, University of Texas at Austin, May 2008, 101 pp. (167271-1)

This scoping study inventories renewable energy alternatives and assesses their impact on the Southwest region’s transportation sector. Biofuel transportation requirements and domestic/international supply chains are illustrated.  A variety of potential solutions are described, including technologies currently commercially available and those still in a research phase.  However, biofuels constitute the focus of this research given the current level of development and potential to impact the Southwest in the near term.  Ethanol is the biofuel most widely marketed at the present time and therefore commands the bulk of this narrative.

The world’s primary producers of ethanol are Brazil and the United States.  These two nations employ different methods to manufacture the fuel from separate crops.  Brazil utilizes sugarcane whereas the United States employs corn.  A four parameter comparison focusing on the energy budget, carbon emissions reduction, land use, and production costs of each biofuel type strongly suggests Brazil’s fuel is superior to the American derivative.  Case studies illustrate how ethanol would reach Texas markets depending on whether the biofuel originated in American corn fields or the Brazilian cerrado.

Additional discussion cites Texas’ limited ability to grow existing commercial biofuels locally.  However, the Southwest region holds greater promise as a producer of next-generation alternatives still undergoing laboratory evaluation.

Keywords: Bioenergy, Alternative Fuels, Economic Impacts, Transport of Alternative Fuels, Transportation Infrastructure

ENTIRE REPORT (Adobe Acrobat File – 2.3 MB)

An Evaluation of Environmental Justice and Environmental Equity: Laws and Issues that Affect Minority and Low-Income Populations

Edward Owens, Gwendolyn Goodwin, Carol A. Lewis and Jeffrey Mallory, Texas Southern University, May 2008, 70 pp. (167921-1)

Environmental Justice and transportation equity concerns pertain to discriminatory outcomes in planning, operation and maintenance, and infrastructure development by state and metropolitan systems. On February 11,1994, President Bill Clinton signed Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations. Two major federal laws, the National Environmental Protection Agency (NEPA) and Title VI of the Civil Rights Act, are highlighted in the Executive Order. This study provides an overview of literature and case studies regarding Environmental Justice issues and concerns. Additionally, the study includes survey responses of state DOT’s and MPO’s about their methods and viewpoints of addressing environmental justice in planning and projects.

Keywords: Environmental Justice, Equity, Low-Income Populations

ENTIRE REPORT (Adobe Acrobat File – 365 KB)

Texas Urban Triangle: Framework for Future Growth

Michael Neuman and Elise Bright, Texas A&M University, May 2008, 34 pp. (167166-1)

This project came into being due to the dramatic transformation of the four core Texas metropolitan areas into an emergent megalopolis: Dallas-Fort Worth, Houston, San Antonio, and Austin. Its aims are two-fold: to provide a framework for decisions about future growth in the fastest growing region of Texas, and to spur further research into the complexities of this vast and rapidly emerging mega-region. The Texas Urban Triangle – 17 million persons spread over 58,000 square miles – is a new urban phenomenon, a triangular megalopolis whose development is not linear and contiguous. This report gives policy makers and investors from all sectors of society the critical knowledge they need to make decisions that will shape the future of Texas. The Texas Urban Triangle is one of the most dynamic urban regions in the nation, and to ensure it continues to flourish, we must build a future based on sustainable growth principles. Our preliminary findings suggest that this is not always the case. Further research needs to be conducted to obtain a complete, detailed, and comprehensive portrait. Nonetheless, even these preliminary findings are robust and point to more sustainable options for the future. Now that this preliminary analysis has been completed, readers are invited to consider the results. The ultimate goals of the project are three-fold:

• To plant the Texas Urban Triangle squarely and firmly into the public imagination of Texans far and wide – to put the Texas Urban Triangle “on the map.”
• To provide a basis for current policy and planning decisions so that a more vibrant and attractive “Heart of Texas” – its metropolises, counties, and cities – provides a more sustainable environment for its residents, and their descendents and newcomers, well into the future.
• To determine what future research, particularly at the regional scale, is needed to provide a sound basis for public policy and private investment decisions.

Keywords: Demographic Projections, Population, Water Supply, Transportation Planning, Sustainable Growth, Texas Urban Triangle, Land Development Options

SUMMARY REPORT (Adobe Acrobat File – 2.6 MB)

Performance Assessment and Comparison between Fixed and Flexible Transit Services for Different Urban Settings and Demand

Luca Quadrifoglio and Xiugang Li, Texas A&M University, May 2008, 46 pp. (473700-00090-1)

In the transit business, planners often face a difficult decision when having to choose what type of operating policy to put in place in a given service area.  In fact, the decision is not straightforward, mainly because the demand for the service is often unknown beforehand and it will depend on the established system itself.  This is especially true for feeder lines, one of the most often used types of flexible transit services connecting a service area to a major transit network through a transfer point.  They often switch operations from/to a demand responsive to/from a fixed‑route policy.  In designing and operating such systems, the identification of the condition justifying the operating switch is often hard to properly evaluate.
In this research, we propose an analytical modeling and solution of the problem to assist decision makers and operators in their choice.  By employing continuous approximations, we derive handy but powerful closed‑form expression to estimate the critical demand densities, representing the switching point between the competing operating policies.
Based on the results of one‑vehicle and two‑vehicle operations for various scenarios and their comparison to simulation generated values, we verify the validity of our analytical modeling approach.  Estimated critical demand densities for the one‑vehicle case and a service area with L=2 and W=0.5 range from 14 to 30 customers/hr/mile².

Keywords: Feeder Transit; Flexible Transit; Demand Responsive; Continuous Approximation; Critical Demand

ENTIRE REPORT (Adobe Acrobat File – 432 KB)

 

A Synthesis of Transportation Emissions Research: Current Status and Future Directions

Lei Yu, Shichen Jia, and Qinyi Shi, Texas Southern University, April 2008, 111 pp. (473700-00049-1)

Transportation related emissions are one of the dominant contributing sources of air pollutants today.   Considering the negative impacts of transportation related emissions on our social and economic environment, extensive efforts have been made by researchers and practitioners attempting to find solutions to reducing emissions.  In order to synthesize these research efforts, various reviews of relevant studies have been conducted by researchers.  However, because of the diversity of the topics, most of existing reviews have only focused on specific and narrowed areas.  Further, none of the existing reviews has attempted to summarize the researchers’ personal opinions on the current research and their prospects of the future research directions.  Therefore, this report is intended to fill this gap by conducting a comprehensive review of the research on transportation related emissions and implementing an extensive survey to the transportation emission professionals.  In the report, a review of existing research and developments on each of the emission related topics is provided, which is followed by a presentation of the respective survey results and analysis.  Future research directions in this field are presented based on the findings of the review and results of the survey.  As a conclusion, current research status is summarized for each topic and recommendations are made for future research directions.

Keywords: Transportation Related Emissions, Review Study, Emission Survey, Emission Sources, Emission Modeling System,  Emission Measurement Technologies, Emission Research Directions

ENTIRE REPORT (Adobe Acrobat File – 1.1 MB)

Evaluation of the Role and Needs of Air Cargo in Texas

Benjamin R. Sperry, Jeffery E. Warner, and Jeffrey D. Borowiec, Texas A&M University, March 2008, 128 pp. (473700-00037-1)

According to the U.S. Department of Transportation, the cargo industry continues to grow, with air cargo identified as the fastest growing segment within the cargo industry. The value of freight moved by air has doubled since 1993 and currently exceeds $2.7 billion per day. During that same period, the typical freight shipment distance increased 40 percent, partly due to the distances of the air cargo movements. Because most air cargo shipments begin and end using trucks, growth in this segment will undoubtedly create additional growth in truck movements in and around the airport environment.

It has been more than 30 years since the state has made a comprehensive review of the air cargo business within its borders. In that time, much has changed in Texas, in the United States, and across the globe. The industry has changed through consolidation and mergers with ground transportation companies, in the services they provide, and in the current level of technology employed. The world is a different place, our economies have been transformed, and the nature of doing business has altogether changed. So far, the impact of growth in air cargo on the Texas transportation system has gained little attention when compared to issues related to seaport traffic.

The research objective for this project is to better understand the operations of the air cargo industry in Texas in order to better accommodate the industry’s needs, provide for a more efficient transportation network, better utilize general aviation facilities, and provide for economic development across the state.
This research identifies the existing demand for air cargo movement in Texas, the ground facilities available to process this demand, and a network that would be efficient and responsive to the needs of industry stakeholders. It also identifies the state’s network of existing air cargo facilities, both those handling existing air cargo activity and those capable of handling air cargo in the future.

Keywords: Air Cargo, Air Freight, Texas Airport System, Economic Trade, Texas Economy

ENTIRE REPORT (Adobe Acrobat File – 8 MB)

An Analysis of the Texas 2002 Safe Routes to Schools Program in Selected Cities

Gwen Goodwin and Yasmina Soria, Texas Southern University, March 2008, 48 pp. (167362-1)

Fewer children are walking to school than ever before. Many researchers contribute this to parents’ fears that the walking environment is unsafe for children. As a result, federal and state programs were created to provide safe routes to school for children. This research will examine the Texas Department of Transportation’s 2002 Safe Routes to Schools Program (SR2S) in and will look at the differences between this program and the new program being implemented under SAFETEA-LU.

Keywords: Safe Routes to Schools, Children Walking in Hazardous Conditions, SAFETEA-LU

ENTIRE REPORT (Adobe Acrobat File – 3.6 MB)

Simulating Land Use Impacts of Highway Development in the Texas Triangle – A Case Study of the Austin Metropolitan Region

Ming Zhang and Tian Haung, University of Texas at Austin, March 2008, 63 pp. (167266-1)

This report is part of an ongoing research on Texas Triangle megaregion, which refers to the region delineated by the metropolitan areas of Dallas/Fort Worth, San Antonio/Austin, and Huston. As the region expects a population growth by approximately 10 million in the next 40 years, it is important to understand the land use/land cover (LULC) implications of the vast growth. Even more important is to understand how public policies and investments (in infrastructure, for example) will influence LULC. The study reported here focuses on the effect of highway construction on LULC through a case study of the Austin, TX area.  The methodologies developed from the Austin case may be applied to the entire Triangle to understand the effects of state-wide transportation strategies, for example, the Trans-Texas Corridor (TTC), on urban development outcome in the region. The Austin case study included three parts. First, historical data on highway constructions in the Austin area are collected and visualized in GIS. Next, land use/land cover maps are derived from classifying LandSat images. A binary logit model is then formulated, quantifying the impacts of transportation accessibility and neighborhoods on the likelihood of LULC change.

Keywords: Land Use/Land Cover Change, Highway Development, Austin, Texas Triangle, GIS

ENTIRE REPORT (Adobe Acrobat File – 11.3 MB)

Investigation of Deer-Vehicle Crash Data and Countermeasure Implementation in Texas

Keith K. Knapp, Texas A&M University, February 2008, 36 pp. (167170-1)

The Deer-Vehicle Crash Information and Research (DVCIR) Center is the only entity in the United States that focuses on the DVC problem and its reduction.  This project investigated the status of DVC data and countermeasure implementation in Texas.  Two meetings on the subject were also sponsored.

The investigation of Texas data revealed an interesting set of characteristics and patterns.  The police-reported data are actually for animal-vehicle crashes (AVCs) and generally only for those incidents resulting in an injury/fatality or the towing of a vehicle.  The data indicate that the total number of police-reported AVCs in Texas decreased from 1992 to 2001 (unlike most of the country), but it was also determined that this was likely due to a change in the crash reporting threshold.  The number of AVC-related injuries, on the other hand, increased dramatically.  The “top ten” AVC counties in Texas generally include those with large or growing traffic volumes and/or favorable deer habitat.  Overall, comparisons of the AVC data and two estimates of these incidents also indicate that the former may not fully describe the AVC problem.  The use of supplemental alternative AVC databases was recommended.

The implementation of countermeasures to reduce collisions between large animals and vehicles in Texas has been limited.  Existing bridges and culverts have been retrofitted for wildlife and new crossings proposed.  Deer crossing warning signs have also been installed.  It is recommended that existing and new countermeasures be implemented and/or monitored.

The two meetings sponsored by this project resulted in the identification and/or prioritization of the non-research activities and the research subject areas that may be funded by the DVCIR Center.  These meetings were essential to the advancement and growth of the DVCIR Center pooled fund project.
Keywords: Deer-Vehicle Crashes, Safety Data, Safety Analysis

ENTIRE REPORT (Adobe Acrobat File – 463 KB)

Estimation of Toll Road Users Value of Time

Dong Hun Kang and William R. Stockton, Texas A&M University, February 2008, 111 pp. (473700-00084-1)

This research examines a new methodology for prospectively estimating the willingness of travelers to use a toll road by combining travel time saved with the income of the prospective customer base.  The purpose of the research is to facilitate network level planning by allowing some reasonable predictions of acceptable toll rates using readily available data and estimation techniques.  Methods of estimating user benefit resulted in simulated distributions of value of user time.  Values of time are linked to census tract income data for the user population to produce value of time as a percent of income as an indicator, which is hypothesized to be a more useful indicator of the travel market than conventional indicators.  Techniques for estimating the travelshed of a toll road are examined.

Results show that considering value of time as a percentage of census tract median income provides an improved portrayal of the toll road market, as usage of the toll road increases with increasing income.  Using census tract median income as the income parameter has shortcomings, in that it produces anomalous results at very low population levels.  Of the two methods of estimating the travelshed, the visual estimation approach was not satisfactory, leaving the analyst to use select link analyses instead.

Keywords: Willingness to Pay, Value of Time, Toll Revenue Forecasting

ENTIRE REPORT (Adobe Acrobat File – 1.9 MB)

Real-Time Data for Hurricane Evacuation in Texas

Darrell W. Borchardt and Darryl D. Puckett, Texas A&M University, February 2008, 45 pp. (167764-1)

In September 2005, the threat of Hurricane Rita to the Houston-Galveston region resulted in the evacuation of more than one million persons from the Texas coastal and urban areas.  This concentration of evacuees overloaded all routes leaving the Houston area, resulting in traffic queues on freeways as long as 36-hours.  While traffic and emergency management personnel had access to real-time traffic information in the urban areas, no such information was available in rural areas where the roadways had restricted capacity.  There was clearly a need to expand video and traffic monitoring capabilities beyond the urban areas to allow for better traffic management in response to evacuations as well as normal traffic operations.

HURREVAC is a restricted-use Internet based computer program used by government emergency managers to track hurricanes and assist in evacuation-related decision making.  The program includes an ETIS (Environment Transport Integrated planning System) module included which allows for inclusion and access to real-time traffic information by emergency managers.  This report documents attempts to complete the integration of the module with traffic data for Texas coastal regions.  It also provides for general equipment and installation guidelines for deployment of video and sensor detection stations along hurricane evacuation routes.  In addition, a list of recommended additional deployments of such monitoring equipment to allow for improved monitoring and managing of traffic during evacuation events in Texas.

Keywords: Hurricane Evacuation, Real-Time Traffic Monitoring, Remote Sensing

ENTIRE REPORT (Adobe Acrobat File – 5.7 MB)

Evaluation and Optimization of Durable Pervious Concrete for Use in Urban Areas

Youngmin Joung, Zachary C. Grasley, Texas A&M University, December 2007, 77 pp. (167163-1)

Although pervious concrete was first used in the nineteenth century, it has only recently begun to increase in popularity. As urban areas expand, the problems associated with runoff management have become more challenging. The focus on the negative environmental effects associated with pavement runoff has also increased. These two issues have spurred the recent interest in pervious concrete pavements; pervious concrete, however, has deficiencies which limit its application as pavements. These limitations include low compressive strength, flexural strength, clogging, and other durability issues. The overall purpose of this project was to provide tools to evaluate and improve the durability and strength of pervious concrete such that it may be more confidently employed in urban roadways. The specific objectives of this project were to

(a) investigate the effect of mixture design on strength of pervious concrete (including the effect of fibers),
(b) evaluate effect of clogging materials on coefficient of permeability,
(c) and investigate the use of the dynamic pressurization test to evaluate the durability of pervious concrete.

This report documents the results of the laboratory testing, and presents recommendations for mixture proportioning. In addition, recommendations are provided for optimizing the balance between compressive strength and permeability.

Keywords: Concrete, Pervious, Permeability, Durability, Fibers

ENTIRE REPORT (Adobe Acrobat File – 1.8 MB)

Trucking Industry Response in a Changing World of Tolling and Rising Fuel Prices

Sharada R. Vadali, Rajorshi Sen Gupta, K. N. Womack, and Madhav Pappu, Texas A&M University, December 2007, 162 pp. (167167-1)

Direct user fees based options are gaining further momentum all across the United States and particularly in the state of TX.  The success of such ventures or projects requires a clear assessment of demand for toll roads among the potential user groups. However, there is too little information about the trucking industry as far as their attitude towards toll roads is concerned.  This lack of attention to response patterns can lead to optimism bias in truck toll forecasts. Through literature reviews, Texas specific focus groups, and surveys this study aims to establish the range in demand variation and route preferences for tolled roads across various segments of the trucking community.  Fuel prices are found to influence route choices and consequently toll road revenue forecasts. In addition to fuel costs, the other trade-offs that emanate from this study include cargo characteristics, haul characteristics, etc. Therefore a better understanding of the demand structure of the trucking firms requires all the relevant trade-offs be taken into consideration.

Keywords: Trucking Industry, Trucks, Route Choice, Tolls, Optimism Bias, Fuel Prices

ENTIRE REPORT (Adobe Acrobat File – 924 KB)

Guidelines for Hurricane Evacuation Signing and Markings

Brooke R. Ullman, Nada Trout, and Andrew J. Ballard, Texas A&M University, December 2007, 22 pp. (0-4962-1)

Based on focus group input and surveys of motorists who have recent hurricane evacuation experience, researchers developed guidelines for various hurricane evacuation signs and markings, including route signs, contraflow signs, emergency shoulder lane signs and pavement markings, etc.

Keywords: Hurricane Evacuation, Signs, Evacuation Route, Evaculane, Emergency Shoulder, Dynamic Message Signs

ENTIRE REPORT (Adobe Acrobat File – 810 KB)

Microsimulation of Household and Firm Behaviors: Coupled Models of Land Use and Travel Demand in Austin, Texas

Saurabh Kumar and Kara M. Kockelman, University of Texas at Austin, December 2007, 147 pp. (167262-1)

Households and firms are key drivers of urban growth, yet models for forecasting travel demand often ignore their dynamic evolution and several key decision processes. An understanding of household and firm behavior over time is critical in anticipating urban futures and addressing transportation, land use and other concerns. Birth and death, migration and location choice are defining events in a household’s and firm’s life cycle, and a study of household and firm evolution requires the estimation and application of models for each of these. Such an exercise is hindered primarily by a lack of quality micro-data. This study develops a basic framework for modeling household and firm demographics using microsimulation. Year 2005 zonal household population and employment point data for the Austin, Texas region, coupled with various, more aggregate data sets, are used to simulate household and firm evolution over time and space.

To ensure a jobs-worker balance, the model may well merit greater synchronization of the population and firm synthesis models. The simulations also suggest a clear shift of firms and households towards more central zones, in part because of the cross-sectional nature of the data sets used to calibrate the location choice models and the lack of density restrictions or other reflections of land-availability constraints on new development.  Essentially, households and firms exhibit a strong centralizing tendency, that Austin’s land market simply cannot allow, due to space and other constraints on new building.  Explicit expressions of such constraints should prove helpful in future implementations of this work.
Keywords:  Microsimulation, Firm Behaviors, Land Use, Travel Demand, Austin, Texas

ENTIRE REPORT (Adobe Acrobat File – 1.1 MB)

Population Updating System Structures and Models Embedded Within the Comprehensive Econometric Microsimulator for Urban Systems (CEMUS)

Naveen Eluru, Abdul Rawoof Pinjari, Jessica Y. Guo, Ipek N. Sener, Sivaramakrishnan Srinivasan, Rachel B. Copperman, and Chandra R. Bhat, University of Texas at Austin, October 2007, 44 pp. (167260-1)

This report describes the development of a population update modeling system as part of the development of the Comprehensive Econometric Microsimulator for SocioEconomics, Land-use, and Transportation Systems (CEMSELTS). CEMSELTS itself is part of the Comprehensive Econometric Microsimulator for Urban Systems (CEMUS) under development at The University of Texas at Austin. The research in the report recognizes that modeling the linkages among demographics, land use, and transportation is important for realistic travel demand forecasting. The population update modeling system focuses on the modeling of events and actions of individuals and households in the urban region. An analysis framework is proposed to predict the future-year population characteristics by modeling the changes to all relevant attributes of the households and individuals. The models identified in the analysis framework are estimated for the Dallas-Fort Worth region. The econometric structures used include deterministic models, rate-based probability models, binary logit models, multinomial logit models, and ordered-response probit models. To verify the outputs from these models, the predicted results for the year 2000 are compared against observed 2000 Census data.

Keywords: Synthetic Population, Travel Demand Forecasting, Land-Use Modeling

ENTIRE REPORT (Adobe Acrobat File – 314 KB)

Short Sea Shipping Initiatives and the Impacts on the Texas Transportation System: Technical Report

C. James Kruse, Juan Carlos Villa, David H. Bierling, Manuel Solari Terra and Nathan Hutson, Texas A&M University, October 2007, 98 pp. (0-5695-1)

This report examines the potential effects of short sea shipping (SSS) development on the Texas transportation system.  The project region includes Texas, Mexico, and Central America.  In the international arena, the most likely prospects are for containerized shipments using small container ships.  In the domestic arena, the most likely prospects are for coastwise shipments using modified offshore service vessels or articulated tug/barges.  Only three Texas ports handle containers consistently (Houston accounts for 95% of the total), and three more handle containers sporadically.  Other ports could potentially offer a limited container service but will most likely require equipment and infrastructure upgrades to be competitive.  The report identifies several triggers, which—if they were to occur—could abruptly change the level of SSS activities in the region.  Even with a doubling of current SSS volumes, the effects on the Texas highway and rail system will most likely be insignificant, with the possible exceptions of Freeport and Brownsville.

Keywords: Short Sea Shipping (SSS), Coastwise, Central America, Mexico, Texas ports, Gulf Intracoastal Waterway, GIWW, Marine Highways

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

Drayage Activity in Texas

Robert Harrison, Nathan Hutson, Jolanda Prozzi, Jason West, Juan Gonzalez and John McCray, University of Texas at Austin, October 2007, 86 pp. (0-5684-2)

The following report chronicles the first year’s findings of project 0-5684. The report characterizes Texas drayage activity while focusing principally on activity occurring at the Port of Houston Barbours Cut Container Terminal, the UP and BNSF rail yards located in Houston, and the border Ports of Laredo and McAllen. The seaport drayage component of the report draws upon information gained from interviews with dray managers and drivers as well as a database of truck activity provided by the Port of Houston. Patterns of delay at the port are broken into processing times that accrue outside and inside the port gates. The rail section describes the Pearland, Englewood, and Settegast yards in Houston. The border analysis relies on interviews with brokers and analysts in describing the emerging patterns of drayage.

Keywords: Drayage, Cartage, Intermodal, Landside Access, Trucking, Port of Houston

ENTIRE REPORT (Adobe Acrobat File – 801 KB)

Transportation Challenges and Issues Facing Rural Texas: A Methodology to Prioritize Rural Transportation Needs

Jolanda Prozzi and Robert Harrison, University of Texas at Austin, September 2007, 56 pp. (473700-00068-1)

Over the past two decades, changes in transportation demand of agriculture and rural industry have interacted with the deregulation of the transportation sector.  This has resulted in the abandonment both of the regulation of truck rates and competition, and of many rural rail links that were deemed inefficient.  Agricultural industrialization and the move towards applying market principles to guide production decisions have had a profound impact on rural transportation infrastructure.  Together with strategic rail decisions to terminate inefficient services, these changes have resulted in larger and heavier truck hauling agricultural products over longer distances on pavements and bridges that were not constructed to withstand these loads.  Clearly there is a need to better understand the strategic challenges and issues as well as the critical role that transportation plays in promoting competitive agriculture and a vibrant rural economy.  The objectives of this project were to (a) explore the rural agriculture / industry-transportation relationship, (b) provide information on major rural stakeholder, industry, and trucking views, (c) highlight the factors that result in greater demands on rural roads from the perspective of the Texas Department of Transportation, (d) present a methodology to prioritize rural transportation needs in transportation planning decisions, and (e) list a number of policy options to address rural transportation concerns.

Keywords: Rural Truck Traffic, Pavement Impacts, Big Boxes, Edge Urbanization

ENTIRE REPORT (Adobe Acrobat File – 276 KB)

Calibration of Pavement Response Models for the Mechanistic-Empirical Pavement Design Method

Rong Luo and Jorge A. Prozzi, University of Texas at Austin, September 2007, 85 pp. (167264-1)

Most pavement design methodologies assume that the tire-pavement contact stress is equal to the tire inflation pressure and uniformly distributed over a circular contact area. However, tire-pavement contact area is not in a circular shape and the contact stress is neither uniform nor equal to the tire inflation pressure.

To precisely account for the effect of actual contact stress on pavement responses, this research evaluates pavement responses under the 3-D non-uniform stresses and under the uniform stress. The studied pavement responses include the horizontal strains at the pavement surface, the horizontal strains at the bottom of the asphalt layer, and the vertical strains at the top of subgrade. A multi-layer linear-elastic computer program, CIRCLY, is used to estimate pavement strains under a number of combinations of tire load, tire pressure, asphalt modulus, asphalt thickness and subgrade modulus. The Asphalt Institute method and the Shell method are used to predict the pavement fatigue life based on the critical strains at the bottom of the asphalt layer calculated by both 3-D stress model and the uniform stress model.

Results show that the vertical contact stress component of the 3-D stresses has the dominant effect on the studied pavement strains. The effects of longitudinal stress component and the transverse stress component cannot be ignored, especially for pavement with a thin asphalt layer. Asphalt thickness, asphalt modulus, tire load and tire pressure have significant effects on the differences in asphalt strains between the 3-D stress model and the uniform stress model, but not on the difference in the vertical strains at the subgrade top. Subgrade modulus shows little effect on the differences in all studied strains predicted by the 3-D stress model and the uniform stress model. Tire pressure has greater effect than tire load on the fatigue life of a pavement with a thin asphalt layer. When the pavement has a thick asphalt layer, the effect of tire load is greater than the effect of tire pressure, and a larger tire load is associated with a smaller number of load repetitions.

Keywords: Mechanistic-Empirical Design, Wheel Load, Tire Pressure, Pavement Response, Non-Uniform Contact Stress

ENTIRE REPORT (Adobe Acrobat File – 1.2 MB)

Developing Appropriate Freight Performance Measures for Emerging Users

Mike Schofield and Robert Harrison, University of Texas at Austin, September 2007, 46 pp. (473700-00073-1)

Federal and state transportation planning and policy has begun to focus on highway performance measurement, balancing goals, performance measures and measurement.  The push toward performance measurement first focused on passenger vehicles, largely ignoring the measurement of freight-related (truck) performance.  The period since 2000 has seen a handful of DOTs examining broad indicators of efficient freight movement, but as of yet, there was no definitive work in the area until a 2003 FHWA funded project began to look into various freight tracking technologies to develop freight performance measures (FPMs), finally selecting a GPS technology widely adopted by U.S motor carriers.  At the time of this study report, the FHWA study worked on data manipulation and graphical representation of highway speeds, but has yet to use the data for alternative performance measures or examine the possibility of using the truck respondents as probe vehicles for real-time ITS applications.  The purpose of this report is to develop a set of universal FPMs, as well as looking into various applications, both real-time and long-term planning, for the truck GPS data collected as part of the FHWA study.

Keywords: Freight Performance Measures (FPMs), Truck Monitoring, Freight Planning, Highway Speeds, ITS

ENTIRE REPORT (Adobe Acrobat File – 1.1 MB)

Testing and Evaluation of Pedestrian Sensors

Shawn Turner, Dan Middleton, Ryan Longmire, Marcus Brewer, and Ryan Eurek, Texas A&M University, September 2007, 42 pp. (167762-1)

The foundation for several pedestrian safety measures is reliable and accurate detection of pedestrians.  The main objective of this study was to evaluate sensors for use in a pedestrian safety test bed in College Station, TX.  The following sensors were installed for use in the pedestrian test bed: 1) MS SEDCO SmartWalk 1400 (curbside detection) and SmartWalk 1800 (crosswalk detection); and 2) ASIM IR 201 (curbside detection) and IR 207 (crosswalk detection).  Several other sensors designed for counting pedestrians and bicyclist on trails also were evaluated: 1) Jamar Scanner, 2) TrafX Infrared Trail Counter, and 3) Diamond Traffic TTC-4420.

The ASIM and MS SEDCO intersection sensors provided fair to mediocre results, with error rates ranging from 9 to 39 percent.  The typical error rates were in the 20 to 30 percent range, which may not be sufficient accuracy for most pedestrian detection applications.  The accuracy of the sensors appeared to be very location-specific, in that pedestrian detection can be more effective in certain situations in which the pedestrian travel area is constrained.  The three trail sensors were able to accurately detect a single pedestrian at typical walking speed or a bicyclist at slow speed (5 to 10 mph).  The Jamar sensor had difficulty counting bicyclists at typical bicycling speed.  All three trail sensors did consistently undercount the actual ground truth counts, with the undercounting being more severe in situations with more pedestrian groups.  This undercounting presents a problem on busy shared-use trails.

Keywords: Pedestrian Detector, Pedestrian Sensor, Trail Counter, Automated Detection

ENTIRE REPORT (Adobe Acrobat File – 2.1 MB)

Development and Evaluation of a Multi-Agent Based Neuro-Fuzzy Arterial Traffic Signal Control System

Yunlong Zhang, Yuanchang Xie and Zhirui Ye, Texas A&M University, September 2007, 122 pp. (473700-00092-1)

Arterial traffic signal control is a very important aspect of traffic management system. Efficient arterial traffic signal control strategy can reduce delay, stops, congestion, and pollution and save travel time. Commonly used pre-timed or traffic actuated signal control do not have the capability to fully respond to real-time traffic demand and pattern changes. Although some of the well-known adaptive control systems have shown advantageous over the traditional per-timed and actuated control strategies, their centralized architecture makes the maintenance, expansion, and upgrade difficult and costly.

Distributed artificial intelligence technologies such as multi-agent systems are well suited for arterial signal control and they have the ability to decompose and accomplish complicated control problems by cooperatively simple agents such that flexibility, efficiency, robustness, and cost effectiveness can be achieved. An in-depth investigation of applying the multi-agent technology in arterial signal control is conducted in this research, and two multi-agent arterial adaptive signal control systems based on neuro-fuzzy reinforcement learning are developed and evaluated using VISSIM simulation and real world traffic data collected in College Station, Texas. The two multi-agent arterial adaptive control systems are compared with optimized coordinated pre-timed and actuated controls. Encouraging results are obtained from both multi-agent control systems.

Keywords: Multi-Agent; Neuro-Fuzzy; Arterial Traffic Signal Control; Reinforcement Learning

ENTIRE REPORT (Adobe Acrobat File – 765 KB)

Evaluating Mexican Truck Safety at the Texas/Mexico Border

Mike Schofield and Robert Harrison, University of Texas at Austin, September 2007, 26 pp. (473700-00071-1)

In June 2004 the U.S Supreme Court ruled that the United States should open its borders to cross-border trucking and so fulfill its treaty obligations under the NAFTA.  Opponents of this action included those who believed that Mexican trucks were unable to meet current U.S. trucking safety standards on a consistent basis.  This report examines this legitimate concern by evaluating border trucking data collected at border safety inspection facilities (BSIF) operated by the Texas Department of Public Safety (DPS).  Safety statistics derived from Mexican trucks crossing the U.S. border are compared with American truck safety data to determine whether there is any warrant for the safety concerns that helped delay the border opening.  The results show that out of service rates are now not significantly different between the two countries.  While increased border inspections since 2001 have reduced out of service citation rates, 2003 and 2004 seem to mark a plateau for 2005 and 2006, where increased inspections may have had a diminished effect in lowering rates.  This, if confirmed by safety data collected for later years, may put into question the benefits of the planned permanent border safety inspection facilities – still not all in service in 2006 – relative to their substantial operational costs and the possible distortions in state truck safety from having a large percentage of DPS staff allocated to the southern part of Texas.

Keywords: Mexican Truck Safety, NAFTA, Safety Inspection Stations, Texas-Mexico Border

ENTIRE REPORT (Adobe Acrobat File – 420 KB)

Comparing Microscopic Activity-Based and Traditional Models of Travel Demand: An Austin Area Case Study

Laura B. McWethy and Kara M. Kockelman, University of Texas at Austin, September 2007, 134 pp. (167862-1)

Two competing approaches to travel demand modeling exist today. The more traditional “4-step” travel demand models rely on aggregate demographic data at a traffic analysis zone (TAZ) level. Activity-based microsimulation methods employ more robust behavioral theory while focusing on individuals and households. While currently not widely used in practice, many modelers believe that activity-based approaches promise greater predictive capability, more accurate forecasts, and more realistic sensitivity to policy changes.

Little work has examined in detail the benefits of activity-based models, relative to more traditional approaches. In order to better understand the tradeoffs between these two methodologies, this paper examines model results produced by both, in an Austin, Texas application. Results of the analysis reveal several differences in model performance and accuracy. In general, activity-based models are more sensitive to changes in model inputs, supporting the notion that aggregate models ignore important behavioral distinctions across the population. However, they generally involve much more calibration and application effort, in order to ensure that synthetic populations match key criteria and that activity schedules match surveyed behaviors, while being realistic and consistent across household members.

Keywords: Travel Demand Modeling, Activity-Based Models, Austin, Texas

ENTIRE REPORT (Adobe Acrobat File – 981 KB)

Compendium of Student Papers: 2007 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, August 2007, 114 pp. (473700-00003-12)

This report is a compilation of research papers written by students participating in the 2007 Undergraduate Transportation Engineering Fellows Program.  The ten-week summer program, now in its seventeenth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects.  The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) analysis of trip generation estimates for mixed-use developments; 2) pedestrian and motorist perception of pedestrian signs in work zones; 3) analysis of driver compliance with work zone speed limits; and 4) nighttime driver needs: an analysis of current guide sign standards and the need for change.

Keywords: Trip Generation Estimates, Mixed-Use Developments, Pedestrian and Motorist Perception, Pedestrian Signs, Work Zones, Driver Compliance, Speed Limits, Nighttime Drive Needs, Guide Sign Standards

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

Development of a Personal Computer-Based Secondary Task Procedure as a Surrogate for a Driving Simulator

Steven D. Schrock, Texas A&M University, August 2007, 188 pp. (473700-00023-1)

This research was conducted to develop and test a personal computer-based study procedure (PCSP) with secondary task loading for use in human factors laboratory experiments in lieu of a driving simulator to test reading time and understanding of traffic control devices such as changeable message sign (CMS) messages.  The importance of this research effort was to show that a PCSP approach could be used to achieve comparable results as a driving simulator approach.  Therefore, a larger sample of subjects can be tested with the PCSP at a much lower cost.  A secondary loading task was developed for the PCSP where subjects were shown CMS messages while simultaneously deactivating randomly displayed buttons in an on-screen control panel.  The secondary task workload could be varied by increasing or decreasing the rate the buttons appeared in the control panel.

One-hundred-twenty-six subjects were tested within the PCSP and in a fixed-base driving simulator.  The subjects were subdivided into three subgroups to compare performance between the driving simulator and the PCSP for alternative CMS messages.  Analysis revealed that essentially the same conclusions were reached with respect to differences in average reading times for each of the three PCSP button display rates in comparison to those reached using the TTI driver simulator.

Keywords: Changeable Message Sign, Driving Simulator, Laptop Computer, Message Comprehension, Message Preference, Message Reading Time

ENTIRE REPORT (Adobe Acrobat File – 1.4 MB)

 

Incorporating Environmental Justice Measures into Equilibrium-Based Transportation Network Design Models

Jennifer Duthie and S. Travis Waller, University of Texas at Austin, August 2007, 35 pp. (167265-1)

This research outlines three major challenges of incorporating Environmental Justice (EJ) into metropolitan transportation planning and proposes a new variation of the user equilibrium discrete network design problem (UE-DNDP) for achieving EJ amongst population groups..  Needed data is compared with what is currently available on spatial distribution of race and income, spatial distribution of trip ends, trip tables, network performance, and cost estimates of improvements.  Several conflicting definitions of equity are offered, as well as applications for each within the context of EJ.  The importance of choosing a correct unit of analysis is discussed, with particular emphasis on how the geographic unit of analysis is a poor proxy for the group unit – that is theoretically required as the analysis’ purpose is to compare performance measures between groups.

Research into the UE-DNDP examines nine potential objective functions focused on maximizing equity of congestion and travel time.  Assuming knowledge of the origin-destination travel matrices by population group, numerical analysis is conducted to assess the performance of each proposed formulation.  The lower level UE problem is solved using the Frank-Wolfe method, and due to the hard combinatorial nature of EJ-UE-DNDP, a selectorecombinative genetic algorithm is implemented to efficiently search the solution space for feasible network improvement strategies.  The results of numerical analysis suggest that both pareto-optimal and utility-based approaches can be successfully applied, and that the most effective formulations minimize the difference between the change in congestion or travel time across population groups due to the selected improvement projects.

Keywords:  Environmental Justice, Transportation Planning, Land Use Improvements, Equity of Congestion and Travel Time

ENTIRE REPORT (Adobe Acrobat File – 296 KB)

Large Truck Crashes in Texas: A Predictive Approach for Identifying Those at Higher Risk

Jodi L. Carson, Texas A&M University, August 2007, 82 pp. (473700-00089-1)

The objective of this research is to characterize large truck safety levels in Texas on the basis of driver, vehicle, cargo, and carrier traits while controlling for the effects of crash and operating environment conditions.  Data to support this investigation considered a three-year time span from January 1, 2004 to December 31, 2006.  During this time, 44,012 total large truck crashes occurred in Texas.  Historical large truck crash and carrier profile information was collected from three sources: the Motor Carrier Management Information System (MCMIS) Crash File, the MCMIS Census File, and the Texas Department of Transportation intrastate carrier database.  Crash severity served as a surrogate measure for large truck safety and was modeled using ordered probit regression methods.  The relationships between the significant (denoted through t-statistics values ³|1.645|) explanatory variables and crash severity were for the most part intuitive and in agreement with previously reported findings.  Despite their individual significance for contributing to large truck crash severity levels, these variables in combination achieved a poor overall goodness of fit (r2=0.0029), likely attributable to missing data, timeline inconsistencies between crash and census data, and repeated measures (i.e., if a carrier was involved in more than one crash between 2004 and 2006, the same carrier characteristics were repeated).  As indicated from the modeling exercise, roadside and carrier-based, on-site safety enforcement practices should be focused towards: (1) single-unit, three-axle and truck tractor (bobtail) vehicle configurations, (2) tank cargo body types, (3) grain/feed/hay cargo classifications, (4) carriers based in Illinois , and (5) private property carriers.  Focusing safety efforts toward these factors, which have shown a significant influence on the severity of a potential crash, provides a more proactive approach to enhancing large truck safety.

Keywords: Large Truck Safety, Commercial Vehicle Safety, Crash Severity, Ordered Probit Regression

ENTIRE REPORT (Adobe Acrobat File – 904 KB)

 

A Probabilistic and Adaptive Approach to Modeling Performance of Pavement Infrastructure

Zheng Li and Zhanmin Zhang, University of Texas at Austin, August 2007, 120 pp. (167267-1)

Accurate prediction of pavement performance is critical to pavement management agencies.  Reliable and accurate predictions of pavement infrastructure performance can save significant amounts of money for pavement infrastructure management agencies through better planning, maintenance, and rehabilitation activities.  Pavement infrastructure deterioration is a dynamic, complicated, and stochastic process with its outcome as the aggregated impact from various factors such as traffic loading, environmental condition, structural capacities, and some unobserved factors.  However, existing performance prediction models are still constrained by inadequate consideration of the dynamic and stochastic characteristics of pavement infrastructure deterioration.
The goal of this research is to develop a probabilistic and adaptive methodological framework that is capable of capturing the dynamic and stochastic nature of pavement deterioration processes.  The ordered probit model and the sequential logit model as probabilistic models are proposed to directly predict the performance of pavements in terms of their condition states by relating the performance to the structural, traffic, and environmental variables.  The proposed probabilistic models were pilot-tested with pavement performance data collected during the AASHO Road Test, yielding good prediction results.  In addition, these models were further enhanced as mechanistic-empirical models and compared with existing performance models.  The comparison results show that the proposed models yield better predictions than the previously developed models in terms of prediction accuracy.  Then, a structural state space model is proposed to characterize the dynamic nature of pavement deterioration.  The proposed structural model has the capability of adaptively updating the performance model with new inspection data by taking advantage of a polynomial trend filter and the Kalman filter algorithm.  The results from a simulation case study indicate that the adaptive algorithm is robust and responsive to structural deviations of the pavement deterioration process.  Therefore, it is concluded that the proposed probabilistic and adaptive methodological framework is reliable and robust to accurately predict pavement performance.

Keywords:  Pavement Performance, Pavement Deterioration, Pavement Infrastructure

ENTIRE REPORT (Adobe Acrobat File – 698 KB)

The Commuter Rail Circulator Network Design Problem: Formulation, Solution Methods, and Applications

Nicholas E. Lownes and Randy B. Machemehl, University of Texas at Austin, August 2007, 145 pp. (473700-00077-1)

Commuter rail is increasingly popular as a means to introduce rail transportation to metropolitan transportation systems.  The long-term benefits of commuter rail include the addition of capacity to the transportation system, providing a quality commute alternative, and shifting land use toward transit-oriented development patterns.  The success of a commuter rail system depends upon cultivating a ridership base upon which to expand and improve the system.  Cultivating this ridership is dependent upon offering a quality transportation option to commuters.  Characteristics of commuter rail systems in the United States present challenges to offering quality service that must be overcome.  Commuter rail has been implemented only on existing rail right-of-way (ROW) and infrastructure (depending upon condition) in the United States.  Existing rail ROW does not often coincide with current commercial and residential demand centers and necessitates the use of a circulator system to expand the service boundary of commuter rail to reach these demand centers. The commuter rail circulator network design problem (CRCNDP) addresses a particular aspect of the commuter rail trip, seeking to improve the performance of the entire system through accurately modeling the portion of the trip from rail station to the final destination.  This final leg includes both the trip on the circulator vehicle and the walking trip from the circulator stop to the final destination.  This report seeks to provide an innovative mathematical programming formulation and solution methodology for the CRCNDP and apply this method to a case study.

Keywords: Public Transportation, Commuter Rail, Route Design, Transit, Accessibility

ENTIRE REPORT (Adobe Acrobat File – 2.4 MB)

North American Transportation Corridor Network

Juan C. Villa and Christopher W. Rothe, Texas A&M University, July 2007, 109 pp. (473700-00091-1)

Trade flows across the three North American countries have increased substantially since the implementation of the North American Trade Agreement (NAFTA), but there is no movement toward developing a true North American Transportation Corridor Network. This report examines two types of North American transportation corridor networks.  The first is a transportation infrastructure network that spans across the three North American countries, including highways, railroads, and port of entries which are all part of a large multimodal transportation network.  The second type of networks analyzed, is a research network that is a collection and collaboration of organizations, individuals, and research that have the goal of improving transportation in North America.  Through this research project, a group of transportation experts from the United States, Mexico and Canada was assembled through a webinar to discuss issues related to a North American transportation corridor plan.  The formation of a North American transportation center is recommended to research and educate government officials on the current and projected state of transportation in North America.

Keywords: North American Transportation, Transportation Corridors, NAFTA

ENTIRE REPORT (Adobe Acrobat File – 3.1 MB)

Go Girl! Facilitating Exploration of Transportation Careers for Girls

Debbie Jasek and Melisa Finley, Texas A&M University, July 2007, 37 pp. (167459-1)

The transportation engineering profession, like every other profession that relies heavily on the engineering, technology and science fields, faces a challenging future.  A recent study by the National Science Board reported a troubling decline in the number of U.S. citizens that are training to become scientists and engineers.  Even more disturbing is the number of females entering engineering and technology fields. Only 9 percent of American engineers are women and only 18 percent of engineering degrees are earned by women. Unless transportation as a profession becomes more focused on encouraging women to study engineering and technology the projected shortages become even more alarming.  In short, the current and future success of the transportation infrastructure and its diverse array of components depend on developing a large cadre of individuals, both male and female, to design, plan, manage, operate, and maintain the vast infrastructure in place.

This study developed a series of one-day conferences and/or events specifically for girls.  These events offered an opportunity to gain hands on experience and insight into what transportation, engineering, and technology careers have to offer. The events provided girls with experiences to encourage interests in science and math, as well as offering exposure and mentoring from female role models that currently work in transportation and engineering fields. By providing a venue that allowed girls to recognize their interests in math and have an early successful experience, two of the crucial factors to encourage careers in technology and engineering are fulfilled. These events were designed in a format that it can be used by any college, university or professional organization as a prototype.

Keywords: Women in Transportation, Women in Engineering, STEM, Transportation Outreach Programs

ENTIRE REPORT (Adobe Acrobat File – 1.8 MB)

A Synthesis of Warm-Mix Asphalt, Joe W. Button

Cindy Estakhri, and Andrew Wimsatt, Texas A&M University, July 2007, 94 pp. (0-5597-1)

This synthesis documents the results of a comprehensive review of worldwide information dealing with the following issues as related to warm-mix asphalt (WMA) technology:

• current state of the art/practice of WMA,
• benefits and costs of WMA technology
• plant modifications to accommodate certain WMA processes,
• mixture design and analysis,
• pavement structural design,
• durability and performance,
• performance-related testing,
• quality control,
• specifications, and
• construction guidelines.

A summary of findings and recommendations is provided. Also included in this synthesis is a complete documentation of the first warm-mix asphalt field trial conducted by the Texas Department of Transportation.

Keywords: Highway Construction, Warm-Mix Asphalt, Hot Mix Asphalt

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

 

Integrating Light Rail Transit into Traditional Bus Systems

Robert Hill and Carol A. Lewis, Texas Southern University, July 2007, 51 pp. (473700-00048-1)

This document identifies those dynamics that facilitate a city’s addition of light rail as a successful component of its urban system, with success deemed to be opening on schedule with minimal start-up issues.  The study examines several new systems and queries the tasks undertaken prior to initiation of service.  The similarities are iterated based on the research findings leading to a defined order for including light rail transit in a previously all bus system with a large portion of attention to role of the operators.

 

Keywords: New Light Rail Systems, Light Rail Start-up

ENTIRE REPORT (Adobe Acrobat File – 301 KB)

An Evaluation of 3-D Traffic Simulation Modeling Capabilities

Sharon Adams Boxill, Texas Southern University, June 2007, 45 pp. (167621-1)

The use of 3D modeling in simulation has become the standard for both the military and private sector. Compared to physical models, 3D models are more affordable, more flexible, and can incorporate complex operations. Unlike a physical model, a dynamic virtual model can react to environmental variables or user input. Additionally, virtual models can be run in the context of other dynamic behaviors such as working traffic lights, functioning train crossing gates, moving vehicles, and air quality analysis.

 A simulation allows you to interact with the space and explore areas that you want to see more closely. And if you want to see more detail in something that hasn’t been modeled, it takes less than half an hour to go back to the model, make changes, and bring it back into the simulation.

Traffic simulation models such as VISSIM, WATSIM, and PARAMICS are on the forefront of integrating 3D visualization packages into their systems. The easy to use multimedia user interface and fast interactive response provide a powerful tool for urban traffic and environmental planners. At this time this technology is still cutting edge and an evaluation of current use and innovations is paramount to wider transportation industry acceptance.

Keywords: Transportation Modeling, Traffic Simulation, 3-D Visualization

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

Characterizing Truck Traffic in the U.S.-Mexico Highway Trade Corridor and the Load Associated Pavement Damage

Feng Hong, Jolanda P. Prozzi, and Jorge A. Prozzi, University of Texas at Austin, April 2007, 58 pp. (167555-1)

As the biggest asset in the transportation infrastructure system, highways play a critical role in a nation’s economic development. Paradoxically, while this development serves as a driving force it is also responsible for significant damage to the highway infrastructure.

The United States, together with Mexico and Canada, signed the North American Free Trade Agreement (NAFTA) in 1992 in an effort to eliminate a large number of tariff barriers to free trade and thus to enhance the economic development of the three countries. Since the ratification of NAFTA in November 1993, U.S. trade with Canada and Mexico has increased dramatically, resulting in a significant increase in truck movements in the countries. In 2004, the Supreme Court ruled against the requirement to undertake an environmental impact study before opening the U.S.-Mexico border, which paved the way for U.S. roads to be opened to long-haul Mexican carriers under NAFTA.

As a result of truck traffic surge, from the perspective of infrastructure preservation, concerns have been raised by highway agencies in the bordering states regarding the increased damage by the growing traffic.

Because of Texas’ proximity to the industrial heartlands of both Mexico and the U.S., the Texas transportation infrastructure is perhaps more affected by the dynamics of free trade than any other state in the U.S. This study is conducted through historical traffic data collected in the U.S.-Mexico trade corridor in Texas. Axle load distributions were investigated in terms of their spatial and temporal characteristics. The main statistical features of traffic loadings, with respect to their damaging effects on highway infrastructure, are captured. An evaluation is presented regarding the prediction of traffic loads, which is not only based on historical data but also accounts for other relevant aspects involving policy and weight limit regulations.

The results presented in this report can furnish highway agencies with better evaluation tools for highway infrastructure management in the trade corridor. The findings could also facilitate policy decisions regarding truck weight regulations and border openings to foreign traffic. To this end, a balance between rational highway infrastructure deterioration and efficient truck freight transportation can be reached.

Keywords: U.S.-Mexico Trade, NAFTA, Truck Volumes, Vehicle Classification, Axle Loading, Weigh-in-Motion

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

A Longitudinal Assessment of the Relationship Between Land Use, Land Values, and Bus Facilities

Gwen Goodwin and Carol A. Lewis, Texas Southern University, March 2007, 43 pp. (167620-1)

This study is designed to measure the potential impacts that transportation facilities have on adjacent properties compared to non-adjacent properties within a quarter mile. Previously done in 1997, this study is updated with information from 2000 and 2004. Census data were obtained to measure demographic changes from 1980 to 1990 and county appraiser’s office data and were used to examine the relationship between socioeconomic variables and the transit facility.

Previously, the 1997 study looked at four transit centers and one park and ride facility in Houston’s Metropolitan Transit Authority (METRO). The current study adds three transit centers from the Central Ohio Transportation Authority (COTA).  Because the transit centers were products of transit oriented development, facilities in Columbus differ in appearance and purpose from Houston’s facilities.  Findings in this study indicate that transit facilities can affect land value.

Keywords: Transit, Transit Oriented Development, Land Values, Bus Rapid Transit, Transit Centers and Redevelopment

ENTIRE REPORT (Adobe Acrobat File – 3 MB)

Assessing Driver Distraction Due to In-Vehicle Video Systems though Field Testing at the Pecos Research and Testing Center

Dillon Funkhouser and Susan T. Chrysler, Texas A&M University, March 2007, 55 pp. (473700-00082-1)

Nine drivers drove 5 laps in an instrumented vehicle around a 10.1 mile closed course containing numerous curves.  Two laps were designated as controls, with each participant also driving one lap while watching a DVD program, one lap while listening to a DVD program and one lap while operating the DVD player.  Participants watching and operating the DVD player were less likely to notice outside events like a lead vehicle applying its brake, or a light being illuminated in their periphery.  During the laps involving the DVD player, they also reacted slower to the events presented in their periphery.  Participants watching or operating the DVD player were also more likely to use their brake and take turns at higher lateral accelerations when negotiating the many curves throughout the test-track.  Finally, participants drove significantly slower when watching the DVD player and marginally slower when operating it.

Keywords: Driver Distraction, Vehicle Entertainment Systems, Instrumented Vehicle Research

ENTIRE REPORT (Adobe Acrobat File – 5.4 MB)

The Texas Rural Summer Transportation Institute

Debbie Jasek and Hector Estrada, Texas A&M University, December 2006, 78 pp. (167143-1)

A considerable number of Texas students grow up in rural or small urban centers that are a significant distance from the large metropolitan areas.  These students are not afforded the same access to the many summer and pre-college programs that are available in large metropolitan areas.  This often affects the students’ decision to further their education and attend colleges or universities.  The Summer Transportation Institute is an established program funded by the Federal Highway Administration’s Office of Civil Rights.  Currently, the STI targets urban students and thereby misses a large segment of the student population of Texas who are potential members for the transportation work force. By developing and conducting a modified Summer Transportation Institute in selected smaller communities and rural areas an audience not previously exposed to transportation career opportunities is reached.  This modified program can be easily implemented for rural Texas students.  This modified program was conducted as a pilot program in three locations.  These locations are similar in that they were rural or semi-rural and at least 35 miles from a major metropolitan area.

Keywords:  Summer Transportation Institute, Summer Programs, STEM, Transportation Summer Programs

ENTIRE REPORT (Adobe Acrobat File – 22.6 MB)

Traffic Engineering Applications of Driving Simulation

Susan T. Chrysler, Alicia A. Williams, and Eun Sug Park, Texas A&M University, December 2006, 141 pp. (167142-1)

Driving simulation has primarily been used to study issues of driver distraction and to evaluate in-vehicle devices.  The visualization and driver performance capabilities of simulators can be applied to more traditional traffic engineering problems as well.  This project aimed to demonstrate the usefulness of a driving simulator in evaluating geometric designs for two-lane roads.  Paved surface width has been shown to be correlated with crash rates and travel speeds on two lane rural roads throughout Texas.  The current project examined how travel lane width, edge line striping, and shoulder width solutions affect driver errors on these roadway types.  In addition, as a result of this project, the library of roadway cross-sections in the driving simulator was increased and is available for use in future studies.

Keywords: Driving Simulator, Rural 2-lane Roads, Lane Width, Shoulder Width

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

Estimation of Travelers’ Values of Time Using a Stated-Preference Survey with Variable Pricing Options

Mark Burris and Sunil Patil, Texas A&M University, December 2006, 75 pp. (167766-1)

This study analyzed data from a stated preference survey of Houston travelers faced with numerous mode choices, including value pricing options.  The study:

1. examined the possibility of using a genetic algorithm to estimate mode choice models while removing the need of making the IIA assumption,
2. estimated nested logit models,
3. attempted to estimate random parameter logit models,  and
4. estimated numerous multinomial logit models.

After comparing different specifications and optimization techniques (namely the genetic algorithm and Newton-Raphson method in the econometric software, Limited Dependent LIMDEP) the multinomial logit model estimation using LIMDEP was found to be more efficient because of easy estimation and a much lower time requirement for estimation. Hence a multinomial logit model was used for estimating the values of travel time savings (VTTS) and the penalty for changing travel schedule for different groups of travelers. The values estimated for the penalty for changing travel schedule were not statistically significant and were therefore not used.  The values estimated for travel time savings were significant and comparable to those obtained in previous studies.  It was found that the average VTTS was 39 percent of the wage rate and was higher for females, non-commuters, households with few vehicles, and the wealthy.

Keywords: Value of Travel Time Savings, Mode Choice Models, Genetic Algorithms

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

Importance of Short Line Railroads to Texas

Jeffery E. Warner and Manuel Solari Terra, Texas A&M University, October 2006, 70 pp. (473700-00027-1)

Short line railroads employ more than 20,000 persons, serve 11,500 customer facilities, and originate or terminate approximately 25 percent of all rail movements.  A good portion of short lines also operate on rail lines that were previously unprofitable and are often the lifeline for many rural agriculture communities.  Texas currently has 41 short line railroads that operate on more than 2,600 miles of track, which represents almost 20 percent of the state rail infrastructure.  The remainder of the track is operated by the three Class I railroads in the state.  Nationwide, there are seven Class I and 545 short line railroads.

The Class I railroads are characterized by long distance movement of freight over high-density rail lines between major markets.  The major commodities are usually transported over a few major lines that stretch across the country, similar to perhaps the interstate highway system.  On the other hand, the short lines operate shorter distances with the primary focus being on serving the customers on the line.

Short line railroads face many obstacles to efficient, profitable operations.  But they also hold great potential, especially with their ability to work closely with shippers to quickly meet changing needs and provide high levels of customer service.  This project examines the issues facing short line railroads, future opportunities, and the importance of these railroads to the state of Texas.

Keywords: Freight Rail, Short Line Railroads, Railroads, Shortline

ENTIRE REPORT (Adobe Acrobat File – 774 KB)

Robust Design and Evaluation of Transportation Networks with Equilibrium Under Demand Uncertainty

Jennifer Duthie and S. Travis Waller, University of Texas at Austin, October 2006, 57 pp. (167556-1)

As long-term forecasts of origin-destination (O-D) travel demands are inherently uncertain, future network performance cannot be predicted with certainty.  Neglecting the uncertainties present can result in inaccurate measures of network performance that may lead to incorrect policy decisions.  This work relaxes the assumptions of determinism and independence of O-D demand in solving user equilibrium assignment.  Insight is presented into the impacts of these assumptions through numerical analyses, where demand takes on various types of normal and lognormal multivariate distributions.  The results indicate that incorrect assumptions of independence can, depending on the actual relationship between demands, lead to significant over- or under-estimation of network performance and incorrect network improvement decisions.

Keywords: Origin-Destination, Travel Demand, Travel Patterns, Transportation Network Performance

ENTIRE REPORT (Adobe Acrobat File – 438 KB)

Can Transit Oriented Developments Reduce Austin’s Traffic Congestion?

Ming Zhang and Chang Yi, University of Texas at Austin, October 2006, 33 pp. (167869-1)

Transit-Oriented Development (TOD) is expected to generate a long list of benefits. Of which reducing car use and relieving traffic congestion are among the top. To what extent can TOD contribute to reduce regional congestion? This paper presents an empirical study of Austin, Texas where a new commuter rail line is under construction and TOD proposals are being developed. The study applied the four-step travel demand modeling to estimate regional travel outcome in one base scenario (No TOD) and two TOD scenarios for the year 2030. Scenario design considers Austin’s TOD ordinance and the All-System-Go Long-Range Transit Plan. Results of the study confirm that TOD would have a great potential to improve regional travel, should it be fully implemented. The improvement is indicated by several measures. First, TOD is estimated to reduce daily PMT by 10-12 million in the region as a whole, or by 3.5-4.5 PMT per person. Second, VMT by the driving modes (SOV and SR) would drop by over 20% while travel by transit and walk/bike increases. The net VMT reduction ranges from 21-27% under the two TOD scenarios. Finally, resulting from TOD practice, the portion of congested roadway in the Austin region is estimated to reduce by 2.2 percentage points, or nearly 700 lane miles. These results provide strong evidence to support TOD practice.

Keywords: Transit-Oriented Development, TOD, Traffic Congestion, Travel Demand Modeling

ENTIRE REPORT (Adobe Acrobat File – 313 KB)

Development of a Phase-by-Phase, Arrival-Based, Delay-Optimized Adaptive Traffic Signal Control Methodology with Metaheuristic Search

Michael Shenoda and Randy Machemehl, University of Texas at Austin, October 2006, 102 pp. (167863-1)

Adaptive traffic signal control is the process by which the timing of a traffic signal is continuously adjusted based on the changing arrival patterns of vehicles at an intersection, usually with the goal of optimizing a given measure of effectiveness. Herein, a methodology is developed in which the characteristics of a traffic signal cycle are optimized at the conclusion of every phase based on the arrival times of vehicles to an intersection, using stopped delay as the measure of effectiveness. This optimization is solved using metaheuristic search procedures, namely tabu search, and embedded in an algorithm in which current vehicle arrival times are detected, arrival patterns over a specified horizon are predicted, the traffic signal timing is optimized, and the timings are sent to a traffic signal controller. The methodology is shown to provide improvement in performance for a number of intersection configurations and traffic regimes over traditional forms of traffic signal control, and the metaheuristic search is demonstrated to significantly reduce the computation time for a solution as compared with other search procedures.

Keywords: Traffic Signal Timing, Adaptive Traffic Signal Control, Metaheuristic Search, Tabu Search

ENTIRE REPORT (Adobe Acrobat File – 691 KB)

Testing and Modeling of Truck Emissions While Idling

Lei Yu, Fengxiang Qiao and Fatemeh Soltani, Texas Southern University, September 2006, 68 pp. (167650-1)

Air pollutant emissions and fuel consumption are the most important problems associated with vehicle idling. Truck idling in particular is more problematic than other vehicles mainly because of the duration of idling and the high amount of emissions produced.   This report is intended to identify the characteristics of truck idling emissions by collecting data using an advanced portable emission measurement system (PEMS), in which the attempt is made to measure actual idling emissions from truck tailpipes and to relate measured emissions to altered pre-testing driving conditions. Employed for the testing is.the On-Board Emission Monitoring system OEM-2100TM, an advanced PEMS. , This equipment can determine the second-by-second emissions of HC, CO, CO2, O2, and NOx in the exhaust gas by a functional equivalent of a repair-grade dual five-gas analyzer subsystem.  Altered driving circumstances considered during truck idling tests include cold starts and hot starts, different distances and durations of driving before the tests, different roadway facility types used while driving, different durations of idling tests, etc. Measured emissions under all the different pre-testing driving conditions are then analyzed and compared. In addition, the measured idling emissions are compared with emissions estimated by the emission factor model MOBILE6 for the particular tested truck.

Keywords: Truck Idling, Idling Emission, Portable Emission Measurement System (PEMS), MOBILE, On-board Emission Monitoring System (OEM)

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Enhanced Freight Sketch Planning Tool for Assessing Multimodal Investment Strategies

Jordan Botticello and C. Michael Walton, University of Texas at Austin, September 2006, 91 pp. (167868-1)

In recent years, there have been dramatic changes in the volume and movement of freight within the US and internationally.  Traditional distribution systems have been replaced by just-in-time driven processes and freight transportation patterns have become much more complex.  Innovations in containerization as well as changes in trade geography have directly influenced international trade movements.  NAFTA and the deregulation of rail, trucking and air in the latter part of the twentieth century also had a large impact on freight movement.  Given these changes, it has become increasingly necessary for transportation planners to look to modes other than traditional highways as solutions for congestion and other transportation problems.  However, public agencies have been challenged to demonstrate and contrast the benefits of these modal investments with traditional highway spending.

During the first phase of the research a spreadsheet based tool, entitled Multimodal Analysis Freight Tool (MAFT) was developed to quantify and evaluate the benefits associated with multimodal freight investments.  However, the tool needed to be further developed to accurately account for the rail and barge components and data regarding these modes was not readily available during the first phase of the project.  This study addresses that issue as well as develops and analyzes a case study involving the rail mode and one involving the barge mode using MAFT.  Additionally, given the uncertainty of assumptions made in the tool, a sensitivity analysis to determine the critical input values is needed.   A critical examination of the output from several case studies was studied to determine the overall effect of these factors on the results. An assessment of the oversimplifications in the tool, due to its sketch planning nature, was undertaken and possible solutions identified.

Keywords: Multimodal Freight Analysis Tool, MAFT, Freight, Multimodal, Rail

ENTIRE REPORT (Adobe Acrobat File – 799 KB)

A Comprehensive Analysis of Built Environment Characteristics on Household Residential Choice and Auto Ownership Levels

Chandra R. Bhat and Jessica Y. Guo, University of Texas at Austin, September 2006, 58 pp. (167860-1)

In this report, we identify the research designs and methodologies that may be used to test the presence of “true” causality versus residential sorting-based “spurious” associations in the land-use transportation connection. The report then develops a methodological formulation to control for residential sorting effects in the analysis of the effect of built environment attributes on travel behavior-related choices. The formulation is applied to comprehensively examine the impact of the built environment, transportation network attributes, and demographic characteristics on residential choice and car ownership decisions. The model formulation takes the form of a joint mixed multinomial logit-ordered response structure that (a) accommodates differential sensitivity to the built environment and transportation network variables due to both demographic and unobserved household attributes and (b) controls for the self-selection of individuals into neighborhoods based on car ownership preferences stemming from both demographic characteristics and unobserved household factors.

Keywords:  Built Environment, Residential Sorting, Self-Selection, Auto Ownership, Integrated Land Use-Transportation Modeling

ENTIRE REPORT (Adobe Acrobat File – 359 KB)

The Impact of Demographics, Built Environment Attributes, Vehicle Characteristics, and Gasoline Prices on Household Vehicle Holdings and Use

Sudeshna Sen and Chandra R. Bhat, University of Texas at Austin, September 2006, 56 pp. (167550-1)

In this report, we formulate and estimate a nested model structure that includes a multiple discrete-continuous extreme value (MDCEV) component to analyze the choice of vehicle type/vintage and usage in the upper level and a multinomial logit (MNL) component to analyze the choice of vehicle make/model in the lower nest. Data for the analysis is drawn from the 2000 San Francisco Bay Area Travel Survey. The model results indicate the important effects of household demographics, household location characteristics, built environment attributes, household head characteristics, and vehicle attributes on household vehicle holdings and use. The model developed in the report is applied to predict the impact of land use and fuel cost changes on vehicle holdings and usage of the households. Such predictions can inform the design of proactive land-use, economic, and transportation policies to influence household vehicle holdings and usage in a way that reduces the negative impacts of automobile dependency such as traffic congestion, fuel consumption and air pollution.

Keywords:  MDCEV Model, Gasoline Prices, Built Environment, Household Vehicle Holdings and Use, Vehicle Make/Model Choice

ENTIRE REPORT (Adobe Acrobat File – 361 KB)

An Investigation on the Environmental Benefits of a Variable Speed Control Strategy

Zhong Wang and C. Michael Walton, University of Texas at Austin, September 2006, 58 pp. (473700-00072-1)

The safety benefits of variable speed limits (VSL) have already been widely recognized. However, the environmental benefits of variable speed limits have been largely ignored. This paper presents a study of the potential benefits of variable speed limits in reducing mobile emissions. A Monte Carlo simulation approach is developed to evaluate the effectiveness of the idea of using variable speed limits to manage and reduce mobile emissions. A case study is performed on the IH-35 corridor in Austin, Texas. The numerical results indicate that on “Ozone Action” days, by managing the freeway/expressway traffic speeds at appropriate levels through VSL, the major pollutants, such as Nitrogen Oxides (NOx) emissions, could be significantly reduced. Considering the large contribution from freeway/expressway traffic to mobile emissions, a variable speed limit strategy could be an effective measure to balance travelers’ need for mobility with conservation of the environment.

Keywords: Air Quality, Emissions, Variable Speed Limit

ENTIRE REPORT (Adobe Acrobat File – 631 KB)

Children and Transportation: Identifying Environments that Foster Walking and Biking to School

Byoung-Suk Kweon, Woo-Hwa Shin, Robert Folzenlogen and Jun-Hyun Kim, Texas A&M University, September 2006, 37 pp. (473700-00031-1)

Few children walk or bike to school. In fact, less than 13% of children in the U.S. walk or bike to school and 85% of trips to school are made by car or school bus (United States Department of Health and Human Services [USDHHS], 2004).  Almost 50% of children walked or biked to school in 1969 (United States Environmental Protection Agency [USEPA], 2003).  Did changes in transportation infrastructure contribute to this reduction in walking and biking? What new changes should be made in transportation infrastructure today to reverse this trend and provide a greater likelihood that children will walk or bike to school?

Although there is very limited understanding of how pedestrian environments influence children’s walking and biking to school, previous research shows that physical environments can foster non-automobile mode choices to school.  Landscape buffers and trees add to parents’ perceptions of their children’s safety and increase their willingness to let their children walk to school (Kweon, Naderi, Maghelal, & Shin, 2004).  Ewing (in press) also found that more children walked to school where there were sidewalks.  In addition, Safe Routes to School programs increase children’s walking to school (Staunton, Hubsmith, & Kallins, 2003).

Physical environments can also be a barrier to children walking and biking to school.  In fact, in a study completed by the CDC (2002, August 16), distance was found to be the number one barrier to children walking to school.  Texas along with many other states established 2mile school walk zones measured by the nearest practical route from the school attended.  However, particularly in the U.S., why distance is the dominant factor in determining walk zone policies and what an appropriate distance might be for walking to school have yet to be consistently documented.

In this research we investigated how additional physical attributes (e.g., street pattern, land use, housing density, environmental content) in the pedestrian environment influence children’s walking and biking to school.  We also measured what school children consider walkable and bikable distances to school.

One hundred eighty six parents from four school walk zones in College Station, TX participated in this study.  They reported their children’s commute modes, routes to school and perceived walking and biking environments to school.  Satellite imagery and spatial data from the College Station Geographic Information Services were used to further investigate distances to school, environmental content, surrounding land use, and street patterns.

Results indicate that children walk more in older neighborhoods with mature trees while they bike more in newer neighborhoods with more sidewalks.  Also children who live on cul-de-sacs walk to school less than those who live on grid streets.  Also, children’s walking is also significantly  related to housing densities and mixed land use.  Contrary to the popular 2mile walk zone guidelines, the mean distance for walking in this study is .71 miles while the mean distance of biking is .93 miles.  On average, children who live beyond 1 mile from their school either ride in a car, car pool, or pay a transportation fee to ride a school bus.  These findings are being used to shape better school walk zone guidelines in support of active and healthy communities.

Keywords: Walking and Biking, Children, School Walk Zone, Pedestrian Environment

ENTIRE REPORT (Adobe Acrobat File – 3.8 MB)

Compendium of Student Papers: 2006 Undergraduate Transportation Engineering Fellows Program

H. Gene Hawkins, editor, Texas A&M University, August 2006, 145 pp. (473700-00003-11)

This report is a compilation of research papers written by students participating in the 2006 Undergraduate Transportation Engineering Fellows Program.  The ten-week summer program, now in its sixteenth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participating in sponsored transportation research projects.  The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) identification of positive guidance deficiencies in urban interchange work zones; 2) driver comprehension of diagrammatic advanced guide signs and their alternatives; 3) performance evaluation of traffic responsive signal control; 4) internal trip capture estimation for mixed-use developments; 5) creating a process to identify a traffic fingerprint and correct altered data; and 6) evaluation of tripcal5 trip generation default models.

Keywords: Work Zones, Positive Guidance Deficiencies, Driver Comprehension, Guide Signs, Signal Control, Trip Capture, Traffic, Data, Tripcal5

ENTIRE REPORT (Adobe Acrobat File – 9.5 MB)

Accurate Speed Estimation Using Single Loop Detector Data

Yunlong Zhang, Zhirui Ye, and Yuanchang Xie, Texas A&M University, August 2006, 74 pp. (167761-1)

Flow speed describes general traffic operation conditions on a segment of roadway. It is also used to diagnose special conditions such as congestion and incidents. Accurate speed estimation plays a critical role in a traffic management or traveler information system.  Data from loop detectors has been a primary source for traffic information, and single loop detectors are the predominant source in many places.  However, single loop detectors do not produce speed output.

Several methods have been developed for speed estimation using single loop detector outputs. These methods, however, have their limitations and are often inaccurate under various traffic conditions. Some of the methods are also difficult to implement. This research project seeks to improve on the existing methods and to increase the accuracy of speed estimation. A new methodology, the Unscented Kalman Filter (UKF) method, is developed for this purpose. Datasets collected from three different freeway locations are used for speed estimation and evaluation of the proposed method. The results show that the proposed method generates accurate and stable estimations of speed. The proposed method is superior to existing methods.

Keywords: Speed Estimation, Single Loop Detector, Unscented Kalman Filter, Large Truck Volume

ENTIRE REPORT (Adobe Acrobat File – 1.5 MB)

Developing a “Recruitment Toolbox” for Transportation Professionals

Jodi L. Carson and Stephanie S. Ivey, Texas A&M University, August 2006, 185 pp. (167765-1)

The transportation engineering workforce in the U.S. is facing a concerning shortage.  While the need to address this shortage is well-recognized, substantive tools and funding mechanisms for making progress towards the recruitment of transportation professionals are lacking.  In cooperation with the Institute of Transportation Engineers (ITE), this project developed a tool – a Recruitment Toolbox – to better support professional participation in local recruitment efforts.

The development process consisted of the following tasks: develop targeted communications plan; develop/distribute solicitation; review other program resources and ITE submissions; develop electronic recruitment toolbox, companion outreach guidelines, and assessment plan; develop/distribute availability announcement, identify venues for “showcase,” and document development process/observations.

The completed Recruitment Toolbox contains a total of 92 activities that cover a range of age levels (Kindergarten through 12th Grade) and topic areas (e.g., environment and energy, planning and urban development, traffic safety, etc.).  The companion Outreach Guidelines focus on understanding your audience and effectively engaging student participants.  The proposed Assessment Plan includes three levels of information gathering: website access, pre-activity survey, and post-activity survey.  The first two products will be available to outreach providers from the ITE website (www.ite.org) beginning January 2007.

The development of the Recruitment Toolbox represents a first step in encouraging higher quality and more frequent outreach to pre-college students.  As a next step, existing activities should be reviewed and enhanced with additional preparatory information and/or more constructive hands-on applications.  Information gathered through the Assessment Plan can help to guide the priority of improvements.

Keywords: Workforce Development, Recruitment

ENTIRE REPORT (Adobe Acrobat File – 3 MB)

Remedial Driver Education in Texas: Does it Do Any Good?

David K. Willis, Texas A&M University, August 2006, 26 pp. (473700-00029-1)

The objective of this report was to assess the effectiveness, if any, of remedial driver education in reducing subsequent traffic crashes and violations in a sample of Texas drivers who took a driver safety course in 2001 (the DSC group), as compared to a control group of drivers who had a violation but did not take a course (the CON group).  The 194,314 drivers examined were a convenience sample of 18-20- year-old Texans obtained for another study.

For every age group, and for the combined group of 18-, 19-, 20-year-old Texas drivers, the DSC group had statistically significantly (p ≤.05) better post-qualifying-event driving records than did the CON group.  Total events were significantly better.  Crashes were significantly better.  Convictions were significantly better.  The findings are generally inconsistent with the research literature, so possible explanations, such as demographic differences between the two groups, were explored, to no avail.

Keywords: Remedial Driver Education, Traffic School, Ticket Dismissal Course, Driving Safety Course

ENTIRE REPORT (Adobe Acrobat File – 242 KB)

Microscopic Datasets: A Novel Approach Applied to Visualization of Spatiotemporal Flow Regions

Paul Nelson and Matthew J. Fields, Texas A&M University, May 2006, 33 pp. (167452-1)

A parsimonious approach to microscopic traffic flow datasets is suggested. This approach is based on provision of minimal data, along with a set of supporting tools termed as feature extraction operators that are intended to provide researchers with the flexibility to extract those particular features of the data that they desire to study. As an illustration of the possibilities of this approach, an attempt is made to validate the hypothesis that traffic flow decomposes into spatiotemporal regions representing one of the four classes of congested flow, shock wave, acceleration wave or free flow. This approach employs the classical conceptual framework of the field of pattern recognition, as applied to microscopic datasets. The specific microscopic dataset employed is that labeled “I-405 Northbound at Mulholland Drive, Los Angeles” in the 1985 study conducted by JHK Associates for the FHWA. The classical approach of plotting and manually analyzing vehicle trajectories is initially employed, to establish some approximation to ground truth. Then it is demonstrated that speed alone is inadequate to support the desired classification. Finally, a 4-means cluster analysis in velocity-acceleration feature space is employed to demonstrate that a spatiotemporal plot of the resulting cluster numbers provides a decomposition more-or-less as expected.

Keywords: Microscopic Data Analysis, Traffic Patterns, Classes of Traffic Flow, Pattern Recognition, K-Means Clustering

ENTIRE REPORT (Adobe Acrobat File – 3 MB)

Innovative Solutions to Transportation Needs in the Colonias

Debbie Jasek and Beverly Kuhn, Texas A&M University, May 2006, 94 pp. (167144-1)

An estimated 400,000 Texas residents, most of whom are legal citizens of the United States, currently live under poor conditions in underdeveloped neighborhoods called colonias along the Texas-Mexico border. They are challenged daily with the simple tasks of seeing their children off to school, going to work, obtaining water for daily use, buying groceries, obtaining quality health care, and having their trash removed. A major link in all of these basic needs is sufficient and affordable transportation. While many areas are gradually working to provide desperately needed infrastructure to these communities, the process is slow and expensive. Innovative and cost-effective solutions are needed to solve immediate transportation needs to help support these Texans in daily life. This research attempts to assess and document innovative, affordable, and cost-effective methods for meeting some of the unique transportation challenges facing residents of the colonias. The overall approach is to provide resources that may help improve the quality of life for these citizens by meeting their transportation needs on a daily basis.

Keywords: Colonias, Transportation, Rural Transit, Colonias Transportation, Rural Transportation Infrastructure, Colonias Infrastructure

ENTIRE REPORT (Adobe Acrobat File – 2.9 MB)

3-D Traffic Simulation Professional Development Seminars 2005 Final Activity Report

Sharon Adams Boxill, Texas Southern University, April 2006, 43 pp. (167652-1)

Society’s increasing dependence on software, technological products, services and systems has been mushrooming far beyond expectations of only a few years ago. The major stimulant for this has been the explosion of the web-based technologies. It is now widely recognized that technology is the “glue” binding together communications, electronics, multi-media, and many other hi-technology products and services, and that it is, perhaps, the largest and most pervasive of global industries. The accelerated growth in this industry has created tremendous opportunities. But it has also presented a number of very tough challenges to the participants – for example, to ensure the supply of adequately developed human resources, to cope with “speed-of-light” technology changes, and to support increasingly rapid product release rates.

This on-going project is designed to fill the gap by addressing the needs of transportation agencies and organizations for supplemental job training to transportation professionals. The educational infrastructure is critical to the continuous professional development of today’s workforce and universities must take the lead in training, upgrading, and retraining workers to support economic growth and retain jobs for the domestic workforce. Companies are continuously driven to employ the latest technologies in their products and in the development of their products. The tremendous rate of change in this sector is placing enormous pressure on organizations, and on their workers, to keep abreast of the changes in order to remain competitive. This is the final activity report for the 3D Traffic Simulation Professional Development Seminars reflects the outcome of the project during fiscal year 2005.

Keywords: Traffic Simulation, Professional Development, Traffic Management, Visualization

ENTIRE REPORT (Adobe Acrobat File – 5.3 MB)

Fibers from Recycled Tire as Reinforcement in Hot Mix Asphalt

Arif Chowdhury, Joe W. Button and Amit Bhasin, Texas A&M University, April 2006, 58 pp. (167453-1)

Previous laboratory and field research has demonstrated that virgin synthetic and cellulose fibers provide important attributes for hot mix asphalt (HMA): reduced asphalt (mastic) draindown during construction for certain types of mixtures, reinforcement which significantly reduces cracking; and, in some cases, reduced rutting. By-product fibers from grinding of scrap tires offer an excellent, low-cost alternative to virgin and cellulose fibers. Currently, most of these fibers are being disposed of in landfills or incinerated.

Two types of recycled tire fibers were evaluated to determine whether they can be used in different types of HMA mixtures as a replacement of currently used cellulose fibers or mineral fiber. The researchers tested three different types of mixtures: stone mastic asphalt (SMA), permeable friction course (PFC), and coarse mix high binder (CMHB) mixtures with two different types of recycled tire fibers, one cellulose fiber, and no fiber. HMA specimens were prepared using all of these combinations and tested using several common laboratory test procedures. The laboratory tests used to evaluate the mixtures were: draindown test, dynamic modulus test, overlay test, indirect tensile strength test, and Hamburg wheel tracking test.

Mixtures containing tire fibers, in most cases, outperformed the mixtures containing cellulose fiber and mixtures with no fiber. Draindown test results clearly revealed that recycled tire fiber can be used in SMA and PFC mixtures as a replacement for cellulose fiber (or mineral fiber) to prevent asphalt draindown during construction. Researchers examined the availability of by-product tire fibers and found them to be readily obtainable in various parts of the USA. The incorporation of recycled tire fiber into HMA does not require any special technique or equipment beyond that typically used for handling other fiber products. The cost of tire fiber will probably be less than cellulose fiber, particularly when tire fiber is available locally.

Keywords: Recycling, Tire Fiber, Overlay Tester, Hot Mix Asphalt, Draindown

ENTIRE REPORT (Adobe Acrobat File – 7.2 MB)

Household Location Choices: The Case of Homebuyers and Apartment Dwellers in Austin, Texas

Michelle Bina and Kara M. Kockelman, University of Texas at Austin, April 2006, 117 pp. (167552-1)

This paper explores the issue of residential location choice for apartment dwellers and recent homebuyers in the Austin, Texas area. An understanding of residential location choice is fundamental to behavioral models of land use and, ultimately, travel demand. Surveys of over 200 apartment dwellers and 900 recent homebuyers offer valuable data on movers and their reasons for moving, as well as their priorities in home type and location selection and tradeoffs from such decisions.

Survey results show that apartment dwellers have different reasons for moving than homebuyers. The top reasons for moving for homebuyers are wanting to own a home and wanting a newer/bigger/better home; many apartment dwellers also reported wanting a newer/bigger/better home (the most frequently chosen response), but they were also much more likely to be moving for an easier commute, new job or job transfer, and planning to attend or graduate from college.

Both apartment dwellers and recent homebuyers reported their level of importance for various housing and location attributes; several of which described various types of access, such as commute time, proximity to shopping availability of bus services, and access to bus services. These features accounted for approximately 40% of the average reported importance for all housing and location attributes for apartment dwellers, but only 25% for homebuyers, suggesting that apartment dwellers place a higher priority on access than homebuyers.

Lifecycle variables, such as living situation and marital status, are important indicators in binary choice experiments and the importance of various measures of accessibility, especially in the case of apartment dwellers. Families in apartments are more likely to choose a location with plenty of parking over a downtown location with limited parking and homebuyers with children favor larger lots over proximity to shopping facilities. Although lifecycle variables are statistically significant in models of stated preferences for homebuyers, current home and location features are more practically and statistically significant, on average. In many instances, homebuyers are more likely to favor improvements that reflect their location choice. For example, households with homes far from the Austin Central Business District (CBD) tend to favor home enhancements over improvements in accessibility despite the fact these locations have lower levels of accessibility, in general. Overall, binary logit and ordered probit model results show that women and non-Caucasians (apartment dwellers and homebuyers) tend to be more concerned with all types of access – commute time, proximity to shopping, availability of bus services, and access to major freeways.

Predictive models of monthly rent, home value, and location offer important insights, while controlling for many key factors. For instance, centrality is valued by residents, so monthly rents fall rapidly within 3 miles of the CBD but taper at further distances, and home values fall linearly by $8,000 for each additional mile away from the CBD, ceteris paribus. As predicted rents and home values decrease with less accessibility (i.e., being further from the CBD), these values increase with apartment/home size (i.e., interior square footage), recognizing the tradeoffs that homes make between various attributes for a given cost constraint.

Additional models of rent and home value isolate structural features of the home from location features. For apartments, location attributes provided higher predictive power (adjusted R2=0.624) when compared to the physical attributes (adjusted R2=0.339). The opposite results occur when looking at homes: the predictive power of the structural aspects (adjusted R2=0.666) is slightly higher than the location information (adjusted R2=0.601). This further supports that apartment dwellers are more concerned with location features than home features, especially in comparison to homebuyers.

Cross-tabulations and a multinomial logit model explore home type choice, for various demographic groups. Understandably, households with many children are more likely to purchase large homes, and households with high incomes are more likely to purchase new homes and larger lots. Attached housing is more prominent for low-income and single-person households.

A multinomial logit location choice model for recent homebuyers shows home affordability and centrality are important to households, as well as the size of homes in the neighborhood. Model segmentation reveals that households with children are more sensitive home affordability and less attracted to central locations than households without children. These results and many others are explained by various model specifications.

Keywords: Location Choice, Land Use, Travel Demand

ENTIRE REPORT (Adobe Acrobat File – 816 KB)

Predicting Truck Tire Pressure Effects Upon Pavement Performance

Feng Wang and Randy Machemehl, University of Texas at Austin, April 2006, 153 pp. (167864-1)

Truck tire inflation pressures have steadily increased in the recent decades. A most apparent effect of the increased tire pressure would be reduction in the tire-pavement contact area, which may in turn result in an increase in the tire-pavement contact stress and then more damaging effects to the pavement. This study uses a Monte Carlo simulation based mechanistic-empirical method to identify and quantify the tire pressure effects on flexible pavement performance.

In this study, measured non-uniform tire-pavement contact stress data for different tire load and inflation pressure conditions and for three popular tire/axle configurations were input to the finite element program ANSYS to compute immediate pavement responses for various asphalt pavement structures. Typical computation results from the finite element program were compared with the results of the linear elastic multilayer program CIRCLY using the traditional tire model in which tire-pavement contact stress is assumed uniformly distributed over a circular contact area and equal to tire inflation pressure. The effects of tire inflation pressure on pavement performance were initially analyzed by inputting the typical computation results into pavement distress transfer functions and variability in loading, pavement or environment conditions was not considered. Critical pavement responses responsible for pavement distresses in bottom-up cracking and rutting were determined. A quick solution method for the prediction of critical pavement responses was developed using regression models that relate critical pavement responses with tire loading and pavement structural conditions. And finally a Monte Carlo simulation based C++ program was developed to predict the effects of increased truck tire pressure on selected pavement structures with variability in loading, pavement, and environment conditions included.

The research study found the traditional tire model and the associated linear elastic multi-layer program tended to overestimate horizontal tensile strains at the bottom of the asphalt concrete layer and underestimate vertical compressive strains at the top of the subgrade layer. The quick solution models developed in this study could predict pavement responses in a good accuracy and be used to replace the time-consuming finite element models. The Monte Carlo simulation program found increased pavement fatigue cracking and rutting would be expected when average tire pressure was increased.

Keywords: Truck Tire Pressure, Tire-Pavement Contact Area, Tire-Pavement Contact Stress, Tire Inflation, Pavement Fatigue

ENTIRE REPORT (Adobe Acrobat File – 2.3 MB)

Background Development and Concept of Operations for a Real-Time Performance Measurement Monitoring System

Robert E. Brydia, Texas A&M University, April 2006, 75 pp. (167147-1)

Recognition and response to incidents on a freeway is a vital function of freeway management. When an incident occurs, an established response mechanism seeks to return the freeway to normal conditions as rapidly as possible. The state-of-the-practice in current systems focuses on identification of the incident and rapid implementation of the established recovery plan. This is one example of an operational strategy used to monitor and improve conditions on the roadways.

What is missing from these systems is systematic feedback on how the plan actually worked and a consistent basis for refining the plan to achieve better results, if possible. The use of a feedback system provides a quantitative basis for assessing the impacts of various operational strategies. That basis is known in other disciplines as system performance measures.

While performance measures have been applied in transportation, the area of transportation operations has lagged behind in implementation. This research proposes an experimental design for a real-time performance measures system as well as a concept of operations for utilizing the information.

Keywords: Performance Measurement, Transportation Operations, Real-Time

ENTIRE REPORT (Adobe Acrobat File – 3.1 MB)

Developing a Diagnostic System for Air Brakes Used in Commercial Vehicles

Shankar C. Subramanian, Swaroop Darbha and K. R. Rajagopal, Texas A&M University, March 2006, 92 pp. (167141-1)

The safe operation of vehicles on roads depends amongst other things, on a properly functioning brake system. Air brake systems are widely used in commercial vehicles such as trucks, tractor-trailers and buses. In these brake systems, compressed air is used as the energy transmitting medium to actuate the foundation brakes mounted on the axles. In this report, a model-based diagnostic system for air brakes is presented. This diagnostic system is based on a nonlinear model for predicting the pressure transients in the brake chamber that correlates the brake chamber pressure to the treadle valve (brake application valve) plunger displacement and the pressure of the air supplied to the brake system. Leaks and “out-of-adjustment” of push rods are two prominent defects that affect the performance of the air brake system. Diagnostic schemes that will monitor the brake system for these two defects are presented. These schemes are corroborated with experimental data obtained from the brake testing facility constructed at Texas A&M University.

Keywords: Modeling, Air Brake Systems, Commercial Vehicles, Diagnostic System

ENTIRE REPORT (Adobe Acrobat File – 3.3 MB)

Modeling the Interaction Between Passenger Cars and Trucks

Jacqueline M. Jenkins and Laurence R. Rilett, Texas A&M University, March 2006, 203 pp. (473700-00015-1)

The topic of this research was the use of distributed computing to improve how the interaction between passenger cars and trucks is modeled. The two focus areas were the development of a methodology to combine microscopic traffic simulation programs with driving simulator programs, and the application of a prototype distributed traffic simulation to study the impact of the length of an impeding vehicle on passing.

The methodology was motivated by the need to provide an easier way to create calibrated traffic flows in driving simulations and the need to capture vehicle behavior within microscopic traffic simulations. The original design for the prototype was to establish a two-way, real time exchange of vehicle data, however problems were encountered that imposed limitations on its development and subsequent use.

The passing study was motivated by the possible changes in federal truck size and weight regulations and the current inconsistency between the passing sight distance criteria for the design of two lane highways and the marking of no-passing zones. Test drivers made passing maneuvers around impeding vehicles that differed in length and speed. The main effects of the impeding vehicle length were found to be significant for the time and distance in the left lane, and the start and end gap distances.

Passing equations were formulated based on the mechanics of the passing maneuver and included behavior variables for calibration. Through a sensitivity analysis, it was shown that increases in vehicle speeds, vehicle length, and gap distance increased the distance traveled in the left lane, while increases in the speed difference and speed gain decreased the distance traveled in the left lane. The passing equations were calibrated using the current AASHTO values and used to predict the impact of increased vehicle lengths on the time and distance in the left lane. The passing equations are valuable for evaluating passing sight distance criteria and observed passing behavior.

Keywords: Distributed Simulation, Traffic Simulation, Driving Simulation, Passing Maneuver, Passing Behavior

ENTIRE REPORT (Adobe Acrobat File – 5.5 MB)

Driver Perceptions of Risk: Potential Approaches to Improving Driver Safety

Laura L. Higgins and Jason Beesinger, Texas A&M University, February 2006, 51 pp. (167451-1)

This research study examined driver perceptions of the reasons for and the risks associated with certain aggressive or negligent driving behaviors, including illegal turns, disregard of stoplights or stop signs, and improper lane usage. A literature search, interviews with DPS officers and “defensive driving” instructors, driver focus groups, and driver surveys in two Texas cities were employed to determine drivers’ perceptions of the risks of selected traffic violations, factors that encourage or discourage unsafe driving behaviors, and how a change in perceived risk may affect future driver behavior.

Keywords: Driver Education, Driver Safety, Traffic Safety, Traffic Laws, Defensive Driving

ENTIRE REPORT (Adobe Acrobat File – 327 KB)

An Assessment of Criteria Used for Transit Friendly Decision-Making

Thabo Moeng and Carol A. Lewis, Texas Southern University, December 2005, 55 pp. (167322-1)

A great deal of attention is being focused on creating more livable communities, as well as implementing smart growth, transit-oriented and generally more sustainable communities. As a result, planners are focusing more attention on multimodal transportation solutions. Regional goals mention the critical nature of planning and implementing environmentally sensitive systems that allow residents a choice in travel mode. A preliminary review of the decision-making criteria used by many local governments, however, shows project selection criteria largely reflective of measures that tend to favor highway-oriented benefits, such as increasing travel speeds. In addition, goals supporting increased non-motorized travel options, increased transit and more environmentally sensitive projects are often less measurable and more related to the nebulous “quality of life” factors. When benefits, such as air quality are measurable, the advantages may be localized and seem insignificant on a regional basis.

This research examines transportation decision-making to determine whether criteria have been broadened to include a more balanced view of transportation, allowing pedestrian and transit options to be assessed based on their full benefits. The study reviews criteria with a focus on identifying non-highway criteria among six selected Metropolitan Planning Organizations (MPOs).

Keywords: Criteria, Decision-Making, Measures of Evaluation

ENTIRE REPORT (Adobe Acrobat File – 632 KB)

Mexican Truck Idling Emissions at the El Paso – Ciudad Juarez Border Location

Josias Zietsman, Juan Carlos Villa, Timothy L. Forrest and John M. Storey, Texas A&M University, November 2005, 161 pp. (473700-00033-1)

This project was co-sponsored by the Southwest University Transportation Center (SWUTC) and Region 6 of the United States Environmental Protection Agency (EPA), and the Border Environment Cooperation Commission. The overall goal of the project was to develop a methodology and to apply this methodology to estimate emissions produced by trucks from Mexico crossing the El Paso-Ciudad Juarez border locations. The specific objectives of the study were to develop a:

1. border crossing fleet profile – profile of the make, model, and year of trucks crossing the two main border bridges;
2. border crossing travel profile -profiles of the drive cycles (acceleration, deceleration, cruising, idling, and creep idling) of trucks crossing the two main border bridges; and
3. border crossing emissions profile -estimates of idling emissions and driving emissions of trucks crossing the two main border bridges

TTI used portable emissions measurement system (PEMS) equipment along with Tapered Element Oscillating Micro-balance (TEOM) equipment operated by Oak Ridge National Laboratory to measure the truck emissions. The project provided good insight into the fleet, travel, and emissions characteristics of trucks crossing the El Paso-Ciudad Juarez border locations.

Keywords: Mexican Trucks, Fleet Profile, Drive Cycle, Emissions, Idling, Border, Air Quality

ENTIRE REPORT (Adobe Acrobat File – 2.4 MB)

The Effect of the New Security Paradigm on Port Infrastructure Development and Finances

C. James Kruse and David H. Bierling, Texas A&M University, October 2005, 104 pp. (167454-1)

Nine public ports account for 88% of all waterborne international trade in the State of Texas. Following September 11, 2001, these ports were required to implement new and additional security measures intended to deter terrorist attacks. This research project provides an overview of the financial aspects of port infrastructure development, the implementation of new security measures, and the relationship between them at these nine Texas ports. The history of the Port Security Grant Program through August 2005 is summarized to provide an understanding of the context in which ports are making financial decisions. This report also describes the financial performance of the ports during the study period (FY 1994 – FY 2004). It examines the funding approaches used to finance asset acquisition and construction, and analyzes both the profitability of Texas ports in general terms and the potential effect of new security-related expenses on port finances. The use of security fees to recoup some of the security costs is explored, as are other potential “financing” mechanisms. Finally, several conclusions and policy concerns that surfaced during the conduct of this research are presented. The information presented in this report was obtained through examination of public financial data, interviews with key executives at the port authorities, investigation of government sources, and through media reports.

Keywords: Port Security, Port Security Grants, Texas Ports, Port Finances, Security Fees, Security Charges, Port Security Policy

ENTIRE REPORT (Adobe Acrobat File – 519 KB)

Best Practices in a University Environment for Homeland Security Research – Testing and Evaluation

David H. Bierling and Stephen S. Roop, Texas A&M University, October 2005, 20 pp. (473700-00019-1)

Universities and other academic institutions are among the settings for conducting homeland security research, including testing and evaluation. This report identifies some of the best practices that may be useful for conducting homeland-security-related test and evaluation in university settings. The report includes advantages and disadvantages that may be encountered in academic environments, and suggests processes and practices that may be utilized in test and evaluation research team formation and project execution.

Keywords: Homeland Security, Test, Evaluation, Research, Best Practice, Academics, Basic Science, Applied Sciences Extension and Training, University, Program Building, Collaboration, Teaming, Organization

ENTIRE REPORT (Adobe Acrobat File – 61 KB)

The Impact of U.S.-China Trade on Multimodal Transportation Systems and the Economies of Texas and Mexico

Leigh Boske, Timothy Box, Moira Foreman, Abhay Kantak and Phillip Savio, University of Texas at Austin, September 2005, 121 pp. (167551-1)

This report examines the dynamics of U.S.-China trade, its implications for the economies of Texas and Mexico, and the role of trans-Pacific transportation supply chains. Part I of the report discusses the emergence of China as a major U.S. trading partner, the extent to which China has become a direct competitor with Mexico in terms of exports to the United States, and opportunities and challenges that this competition poses to the economic growth prospects of Texas. Part II addresses transportation infrastructure and logistics within China, trans-Pacific ocean shipping lines and their scheduled services, U.S. West Coast ports and connecting landbridge rail services, and alternative routes via the Panama Canal, Mexico’s West Coast ports, and the Suez Canal. Two appendices contain information on trends in U.S. international trade and trans-Pacific maritime routes and services.

Keywords: U.S.-China Trade, Supply Chain, U.S. Transport Network

ENTIRE REPORT (Adobe Acrobat File – 4.8 MB)

Austin Commuter Survey: Findings and Recommendations

Chandra R. Bhat, Aruna Sivakumar, Sudeshna Sen, Jessica Guo and Rachel Copperman, University of Texas at Austin, September 2005, 59 pp. (167240-1)

The purpose of this research is to present the major findings and recommendations of a University of Texas (UT) commuter research study that (1) Examined the demographic, employment, and overall travel characteristics of Austin area commuters, and analyzing how these characteristics impact commute travel choices and perceptions, (2) Developed a framework for evaluating the effect of alternative congestion alleviation strategies on commute mode choice, and (3) Identified broad and important issues that have to be recognized when designing and analyzing a comprehensive mobility plan for Austin. The UT research study was based on a web-based survey of Austin area commuters undertaken between December 2003 and March 2004. The data from the web-based survey was weighted appropriately to be representative of the Austin area commuter population.

Keywords: Travel Time Reliability, Mixed Logit, Activity-Based Analysis, Commute Travel, Mode Choice

ENTIRE REPORT (Adobe Acrobat File – 395 KB)

Experience with Flex Route Transit Service in Texas

Laura L. Higgins, Linda K. Cherrington, Texas A&M University, September 2005, 62 pp. (167148-1)

Flex-route and feeder bus services are solutions that more public transit providers may find advantageous to explore as they try to serve increasingly spread-out and suburban populations while maintaining cost-effective operations. This study examined the experiences of The T, VIA, DART, and other selected transit agencies in Texas who have operated flex-route bus services, examining their objectives for operating the service, experiences, and lessons learned.

Keywords: Transit, Feeder Bus, Route Deviation, Flexible Routing

ENTIRE REPORT (Adobe Acrobat File – 1.9 MB)

The Integration of GIS and Transportation Modeling: A State-of-the-Practice Review

Sharon Adams Boxill, Texas Southern University, September 2005, 43 pp. (473700-00043-1)

One of the factors that continuously affect the quality of life and the desirability of metropolitan areas as a place to live and work is an effective local transportation system. As individuals, businesses and government search for ways to relieve congestion and reduce travel time, the role of geographic information systems (GIS) in relation to transportation planning, analyzing, evaluating, and planning of transportation networks and systems becomes more critical. A powerful relationship exists between GIS and transportation modeling systems. State departments of transportation (DOTs) and metropolitan planning organizations (MPOs) have begun to utilize Environmental Systems Research Institute’s (ESRI) ArcInfo, ArcView, and Intergraph’s GeoMedia Suite with transportation models; however, these activities have not been documented together in a single source. The purpose of this report is to document the active use of GIS for transportation (GIS-T) (if any) at the 50 state Departments of Transportation and Metropolitan Planning Organizations.

Keywords: GIS, Transportation Modeling, Transportation Planning, GIS-T

ENTIRE REPORT (Adobe Acrobat File – 594 KB)

An Examination of Successful Mixed Use in Transit Oriented Development as Conceptually Applied to the Proposed Ambassador Way Transit Station in Houston, Texas

Tammye Davis and Carol A. Lewis, Texas Southern University, September 2005, 64 pp. (473700-00046-1)

Through the implementation of a state of the art light rail system, Houston has relinquished its title as the largest city in the US without a fixed guide way transit system. METRORail has been designed with the intent to enhance environmental, social, and economic development. The rail is one of a number of mobility improvements to counter Houston’s ranking as among the top ten worst cities in terms of traffic congestion. This is in some measure due to lower density, vast residential and commercial development patterns that force people to drive more frequently and over longer distances. However, in recent times people have rediscovered that building in proximity to “good public transit connections” is an amenity that attracts the interest of renters, homebuyers and many businesses. This realization has been formed out of a 30-year debate about rail transit systems. It has become apparent that a Transit Oriented Development (TOD) in Houston can work.

According to the Urban Land Institute (ULI), TOD is considered a major way to create more securely clustered, pedestrian friendly, mixed use projects that can increase rail ridership. The purpose of this study is to investigate, analyze and evaluate the suggested and implemented successful principles of Transit Oriented Development system and relate the patterns to the Houston’s Ambassador Way Transit Station. This research will be useful for transit organizations and other stakeholders engaged in Houston’s new transit developments, to ensure that nearby growth will produce adequate numbers of riders to nourish transit and initiate a desire to optimize land use around the Ambassador Way Transit Station community. This work also will serve as a guide to communities, designers and developers who may not initially recognize the basic valuable principles that underlie any Transit Oriented Development project.

Keywords: Transit-Oriented Development, Transit Land Use Coordination

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Analysis of Texas Speed Limit Laws and Fatality Accident Rates

Ronald E. Goodwin and Ursurla Anderson, Texas Southern University, September 2005, 55 pp. (167320-1)

Safety on Texas’ interstate highways receives constant media attention. From issues such as truck safety and seat belt requirements, the highways remain a focal point of scrutiny and federal funds. As vehicle miles traveled (VMT) continue to increase, there is little hope that Texans will be giving up their sport utility vehicles anytime soon. Therefore, the attention must be towards strategies to establish policies that enhance safety while not hindering mobility. This project seeks to determine if the increase in speed limits from 1996 to 1999 resulted in an increase in fatal accidents in Texas. The data focused on a select set of variables and the data from Texas will be compared to nationwide figures in order to determine if there were any similarities in the number of fatal accidents.

Keywords: Highway Safety, Speed Limits, Highway Fatalities

ENTIRE REPORT (Adobe Acrobat File – 404 KB)

Compendium of Student Papers: 2005 Undergraduate Transportation Engineering Fellows Program

Steven D. Schrock, editor, Texas A&M University, August 2005, 201 pp. (473700-00003-10)

This report is a compilation of research papers written by students participating in the 2005 Undergraduate Transportation Engineering Fellows Program. The ten-week summer program, now in its fifteenth year, provides undergraduate students in civil engineering the opportunity to learn about transportation engineering through participation in sponsored transportation research projects. The program design allows students to interact directly with Texas A&M University faculty members and Texas Transportation Institute researchers in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) a managed lanes traffic and toll revenue study for the San Antonio Northeast Corridor; 2) an investigation between tire hits on raised pavement markers and traffic volume; 3) an analysis of age and education characteristics in the comprehension of changeable message signs; 4) an analysis of reading time and comprehension of AMBER alert messages presented on simulated changeable message signs; 5) an analysis of noises from vehicle tire interactions with rumble strips; 6) a study of driver understanding of innovative diagrammatic guide sign formats; 7) the development of a conceptual model to evaluate the performance of on-premise business signs; and 8) the development of a transportation performance monitoring plan for the Texas Medical Center in Houston, Texas.

Keywords: Managed Lanes, Raised Pavement Marker Performance, Changeable Message Signs, Rumble Strips, Diagrammatic Signs, On-Premise Business Signs, Transportation System Monitoring Plan

ENTIRE REPORT (Adobe Acrobat File – 9.1 MB)

Identifying and Quantifying Operational and Safety Performance Measures for Access Management: Micro-Simulation Results

William L. Eisele and Casey M. Toycen, Texas A&M University, August 2005, 105 pp. (167725-1)

This research report summarizes the activities of a research project intended to identify and quantify appropriate operational and safety performance measures that can be used for investigating access management treatments. Specifically, the research had three objectives: 1) assess the state-of-the-practice relative to performance measures that are applicable to access management and identify existing and/or new measures-particularly measures that can capture the safety benefits of access management treatments, 2) perform micro-simulation using the identified measures on two selected case study corridors and on three theoretical corridors to demonstrate the application of the measures, and 3) develop guidance for applying the performance measures for evaluating roadway improvements that include access management treatments (e.g., raised medians, driveway consolidation) and incorporating them into the transportation planning process.

The research will be useful to practitioners as it identifies desirable input and output characteristics for individuals searching for a micro-simulation tool to use for assessing the impacts of access management. It also identifies surrogate safety measures related to time-to-collision (TTC), and incorporates them into a micro-simulation model (VISSIM) as a demonstration of how both safety and operational impacts might be investigated in the same software package. Generally, the results appear intuitive-particularly at lower volumes and for the theoretical corridors.

The research report also discusses how the safety measures can be incorporated into the traditional transportation planning process. It also cautions that corridor improvements are very case specific and illustrates how micro-simulation, when calibrated appropriately to field conditions, provides a tool to estimate the effects of combined corridor characteristics. Finally, the research report concludes with future research needs that can enhance the state-of-the-practice in this area.

Keywords: Access Management, Medians, Driveway Consolidation, Time-to-collision, Micro-simulation, Safety, Conflict Points, Performance Measures

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

The Development of the Texas Summer Aviation Institute and the Implementation of a Pilot Program in Conroe

Texas, Jeffrey D. Borowiec and Debbie Jasek, Texas A&M University, August 2005, 91 pp. (167456-1)

Attracting students to the transportation profession can be a difficult task. Attracting them to aviation careers is that much more daunting. Students across the state progress through the public education system with little or no exposure to aviation. Students enter high school and college with little understanding of and appreciation for aviation and the opportunities and challenges that may await them in the future. This summer aviation institute allowed 10th and 11th graders to experience the effects of science, math, and engineering as they participate in aviation-related activities. They also participated in hands-on activities and problem solving initiatives that incorporated team building and cooperative learning to teach principles of flight, aerodynamics, aerial navigation, Newton’s Laws, aircraft instrumentation, Bernoulli’s Principle, materials science, general math, and the history of flight.

The major objective of this effort was to create a two-week Summer Aviation Institute modeled after the Texas Summer Transportation Institute (TSTI) with a core curriculum that can be easily and economically implemented in any region of the State. This core curriculum included speakers, field trips, videos, and hands on activities highlighting the importance of aviation and exposure to aviation career opportunities. The modules and the related activities will be TEKS based. This project includes conducting a pilot program that includes implementing and demonstrating the two-week program. It is expected that this will take place in the Houston area.

Keywords: Educational Outreach, Summer Transportation Institute, Transportation Education, Aviation Education, Rural Summer Programs

ENTIRE REPORT (Adobe Acrobat File – 4 MB)

Evaluating Bicycling Commuter Experiences at Texas A&M University and Adjacent Areas in the City of College Station, Texas

Robin Rabinowitz and Debbie Spillane, Texas A&M University, August 2005, 76 pp. (167455-1)

The university-oriented community of College Station, Texas offers a great opportunity for bicycle commuting. Both the City of College Station and Texas A&M University (TAMU) have taken steps to add facilities for pedestrians and bicycles in and around campus areas. The goal of this project was to assess existing conditions to determine the potential to further increase bicycle use in the community. We focused our research on the TAMU campus and adjacent areas, as the university is the largest trip generator in this community.

Two surveys of bicycle commuters were conducted in which bicycle commuters reported inadequate pathways (including poor pavement conditions as well as too few pathways), aggressive motorists, and difficult intersections/traffic signals as their major obstacles to bicycling to campus. Fifty-five percent of survey respondents would like to have more and/or better bicycle pathways. Comments indicated that separate, dedicated pathways would be preferred by bicyclists, and 69 percent of survey respondents said they would bicycle more if a safe and direct route was available.

The research team conducted a survey of non-bicycle commuters in which 42 percent of respondents, for reasons not related to the bicycling environment, said they could not be encouraged to bike. Fourteen percent said that improving pathways might encourage them to bicycle commute, and 5 percent stated that safety concerns are their primary reason for not bicycling to campus.

The researchers also conducted a manual count of commuter bicyclists and found that of the approximately 45,000 students enrolled at TAMU, 1,906 enter campus by bicycle on a typical class day. Available data confirmed that approximately 22,000 students enter campus daily through modes other than bicycle. Based on the information gathered in this research project, the researchers estimate that approximately 500 additional students may bike to campus daily if safe and direct routes to campus were available to them.

Keywords: Bicycle, Bicycle Commuting, Bicycle Count, Bicycle Survey, University Bicycle

ENTIRE REPORT (Adobe Acrobat File – 6.2 MB)

A Framework for Developing Integrated ITS Solutions to Improve Traffic Operations

Zhong Wang and C. Michael Walton, University of Texas at Austin, June 2005, 63 pp. (167248-1)

The overall objective of this study is to assist transportation agencies in developing appropriate ITS strategies to improve traffic operations. This report summarizes the effort in applying innovative methods for ITS planning and ITS evaluation. First, the authors present a study using FHWA ITS Planning Process Version 2.1 to develop appropriate ITS strategies to accommodate local needs. A case study was performed in Austin, Texas to illustrate the whole procedure. The results indicate that by incorporating the National ITS Architecture and IDAS, the FHWA ITS Planning Process could be more applicable to the regional ITS planning. Next, a multicriteria decision analysis method is presented for ITS alternative comparison and selection. The multicriteria approach developed in this study can be applied to identify the best ITS alternative among several candidates. An iterative ELECTRE-I procedure was employed to compare various ITS alternatives and identify the best one. With a case study in Austin, TX, the approach was illustrated and its applicability was proven. Finally, recommendations for further research activities are given at the end of the report.

Keywords: ITS Evaluation, ITS Planning, Decision Analysis, Multicriteria Approach, National ITS Architecture, IDAS, ELECTRE-I

ENTIRE REPORT (Adobe Acrobat File – 2 MB)

Methodologies for Reducing Truck Turn Time at Marine Container Terminals

Nathan N. Huynh and C. Michael Walton, University of Texas at Austin, May 2005, 146 pp. (167830-1)

One of the prominent issues container terminal operators in the US are seeking to address is how to effectively reduce truck turn time. Historically, truck turn time has received very little attention from terminal operators because port congestion has never been a barrier to their operations. However, with the recent explosive growth in containerized trade, terminals are straining to accommodate the truck traffic that moves through them. The heavy intermodal truck traffic is not only causing problems for terminal operators but for the public as well. The emissions from idling trucks are a hazard to people working and living in and around the terminals. With containerized trade volume expected to double in the next ten years, the problems associated with port congestion could get worse if measures are not taken to address the source of the problems.

Terminals in some areas of the US are now required by state law to expedite the flow of trucks through their terminals. In California, any truck that idles for more than thirty minutes will result in a $250 fine to the terminal operator. This law has prompted terminal operators to look for ways to move trucks through their terminals faster, not just to avoid paying the fine, but also to lower the inland transportation cost of shipping a container via their terminals to remain competitive.

This research investigates the two measures terminal operators are taking to reduce their terminals’ truck turn time. The first measure is investing in additional yard cranes to facilitate the handling of containers. To this end, this research seeks to assist terminal operators in deciding whether or not to make the investment. Statistical and simulation methodologies are developed to better understand the availability of yard cranes versus truck turn time. The second measure is implementing a truck appointment system to regulate the number of trucks into the terminal. To this end, this research seeks to assist terminal operators in evaluating the consequences of limiting truck arrivals into the terminals. Furthermore, this research develops a methodology to assist terminal operators in implementing the truck appointment system, should they decided to have one.

Keywords: Robust Optimization, Simulation, Marine Container Terminals, Port Congestion, Container Throughput, Truck Turn Time, Yard Cranes, Arena

ENTIRE REPORT (Adobe Acrobat File – 2.6 MB)

Methodology for Quantifying Pavement Damage Caused by Different Axle and Load Configurations

Karan Kapoor and Jorge A. Prozzi, University of Texas at Austin, April 2005, 108 pp. (167827-1)

In the past, pavement design has been based on empirical approach, which is accurate if used within the range of design factors over which the methods were developed. However, in an environment of constantly changing designs, materials, traffic characteristics, and construction techniques, there is a continuous need for a design approach which can account for these changing scenarios and increased weight limits. The mechanistic-based analysis approach developed through research project NCHRP 1-37A (Development of the 2002 Guide for the Design of New and Rehabilitated Pavement Structures) explains the scientific basis for pavement deterioration and is used for this research. As part of this research, a number of pavement structures were modeled, different axle load levels were applied, and the response and performance of the pavement sections were estimated under five typical environmental conditions, which fully represent the state of Texas. This report presents and discusses the results of the mechanistic-based performance analysis and the use of the results together with statistical tools to develop a methodology for estimating load-associated pavement damage. The methodology also enables Equivalent Damage Factors (EDF) to be determined for similar pavement structures and environmental conditions.

Keywords: Pavement Design, Mechanistic-Empirical, Equivalent Damage Factor (EDF)

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

Texas Colonias Van Project: An Aspect of Transportation in Underserved Communities

Dock Burke, Kermit Black and Patricia Bass Ellis, Texas A&M University, March 2005, 31 pp. (466630-1)

The primary goal of this van project is to increase the access of colonia residents to the education, workforce, health, human services, youth and elderly programs available at community resource centers established within colonias by the TAMU Colonias Program and at locations elsewhere in the surrounding areas.

Keywords: Colonias, Transportation Service, Van, Shuttle, Rural

ENTIRE REPORT (Adobe Acrobat File – 753 KB)

Combined Traffic Signal Control and Traffic Assignment: Algorithms, Implementation and Numerical Results

Chungwon Lee and Randy B. Machemehl, University of Texas at Austin, March 2005, 289 pp. (472840-00074-1)

The nonconvex combined traffic signal control and traffic assignment problem is examined using four different algorithms and four example networks. The heuristic iterative approach has been widely used (1) without any justification regarding solution quality and (2) without any treatment of the problem of nonconvexity. This is the first study designed recognizing the nonconvexity of the combined problem and examining quality of different algorithm solutions with convergence pattern analysis. Drivers are assumed to follow Wardrop’s first principle and link performance is described by the Webster curve. Origin-destination matrices are assumed fixed, green time per cycle ratios and cycle length are decision variables, and total system travel time minimization is the control objective. The iterative approach sequentially performing assignment and signal optimization finds mutually consistent points where flow is at user equilibrium and signal setting is optimal. Three different local search algorithms with six variations regarding gradient calculation are implemented. To counter the nonconvexity, two stochastic global searches, simulated annealing and a genetic algorithm are applied. Complex signal schemes with overlapping movements and multiple phases are included in the developed codes. The codes are preliminarily tested to address characteristics of the algorithms. Comprehensive experiments are designed using five different demand levels and four different size networks. An aggregate measure to determine the similarity of solutions by different algorithms indicated that the mutually consistent solutions are quite different from the other algorithm solutions and the difference grows as demand increases. Regarding solution quality, each algorithm has a relatively superior combination of demand level and network Size. The iterative approach and local searches converge quickly but the two global searches converge slowly. Numerical results confirm that the iterative approach is not always desirable and should be carefully applied at high demand in networks. At high demand, however, no algorithm is always outperforming. To improve code performance, a hybrid algorithm of global and local/iterative search utilizing their exclusive merits simultaneously and efficiently should be developed.

Keywords: Traffic Signal Control, Convergence Pattern Analysis, Signal Optimization, Iterative Approach

ENTIRE REPORT (Adobe Acrobat File – 2.7 MB)

Applications of Geocoded Traffic Crash Records and Crash-Risk Mapping Technology in Roadway Safety Improvement Projects

Saw-Pin Miaou, and Joon Jin Song, Texas A&M University, March 2005, 65 pp. (167145-1)

In recent years, there has been a renewed interest in applying statistical ranking criteria to identify sites on a road network, which potentially present high traffic crash risks or are overrepresented in certain type of crashes, for further engineering evaluation and safety improvement. This requires that good estimates of ranks of crash risks be obtained at individual intersections, road segments, or analysis zones. The objective of the study, on which this report is based, was to explore some of the issues raised in recent roadway safety studies regarding ranking methodologies in light of the recent statistical development in space-time generalized linear mixed models (GLMM). First, general ranking approaches are reviewed, which include naïve or raw crash-risk ranking, scan based ranking, and model based ranking. Through simulations, the limitation of using the naïve approach in ranking is illustrated. Second, following the model based approach, the choice of decision parameters and consideration of treatability are discussed. Third, several statistical ranking criteria that have been used in biomedical, health, and other scientific studies are presented from a Bayesian perspective. Their applications in roadway safety are then demonstrated using two data sets: one for individual urban intersections and one for rural two-lane roads at the county level. As part of the demonstration, it is shown how multivariate spatial GLMM can be used to model traffic crashes of several injury severity types simultaneously and how the model can be used within a Bayesian framework to rank sites by crash cost per vehicle-mile traveled (instead of by crash frequency rate). Finally, the significant impact of spatial effects on the overall model goodness-of-fit and site ranking performances are discussed for the two data sets examined. The report is concluded with a discussion on possible directions in which the study can be extended.

Keywords: Roadway Safety, Problem Site Identification, Bayesian Ranking Method, Small Area/Domain Estimation Problem, Disease Mapping Problem, Generalized Linear Mixed Model, Decision Parameter, Treatability, Statistical Ranking Criterion, Spatial Dependence

ENTIRE REPORT (Adobe Acrobat File – 6.2 MB)

Providing Personalized Traffic Safety Information to the Public: Using Web-Based Geographical Information System Technologies

Saw-Pin Miaou, Raghav Tandon, and Joon Jin Song, Texas A&M University, February 2005, 43 pp. (167424-1)

Due to their size and complexity, traffic crash records and related databases have not been particularly accessible to the general public. As more households, schools, and libraries are being equipped with high-speed desktop computers and as more subscribe to broadband communication services, providing Personalized Traffic Safety Information (PTSI) to individuals through the Internet will soon be a cost effective means of sensitizing and educating the public on traffic safety issues and on roadway conditions in areas and roads of personal interest to them. The main objective of this study was to explore and test the capability of existing web-based geographical information system (Web-GIS) technologies to personalize and disseminate traffic safety information to the public in a cost-effective manner. The Web-GIS technologies explored were those that could provide users with on-line access to safety databases and allowed users to visualize the distribution and statistics of traffic crashes geographically and learned about the nature of these crashes over the Internet. In particular, this study looked into the Internet Mapping (IM) technology that has been significantly advanced in recent years. To test these technologies, this project selected Brazos County, Texas, as a testbed.

At the time of this study, the locations of crash records and associated road inventory data were not georeferenced in Texas. To meet the research need, an important part of the study was an attempt to develop an efficient and accurate way of geocoding historical traffic crashes using Geographical Information Systems (GIS). In addition, under a joint effort between this and another research project, a prototype web-based traffic safety information system for Texas was developed by this research team. The system was named Web-Based Traffic Safety Information and Analysis System (W-TSIAS). It consists of a set of semi-automated GIS-based procedures for geocoding and is coupled with a suite of Internet mapping capabilities, which allow locations and attributes of geocoded crashes, road inventory, and related data to be securely accessed, viewed, and queried remotely through a typical web browser. One of the functionalites of W-TSIAS was to provide PTSI to the public.

Keywords: Personalized Traffic Safety Information, Traffic Safety Record, Geographical Information System, Geocoding, Internet Mapping

ENTIRE REPORT (Adobe Acrobat File – 6.7 MB)

Evaluation of the Joint Effect of Wheel Load and Tire Pressure on Pavement Performance

Rong Luo and Jorge A. Prozzi, University of Texas at Austin, January 2005, 188 pp. (167245-1)

Most pavement design and analysis procedures predict performance based on the expected damage of the pavement structure under the traffic loads expected during the entire design life. Some failure criteria are primarily dependent on wheel loads and almost independent of contact stresses. Other failure criteria, however, are primarily dependent on normal and shear stresses, not on the load magnitude. The effect of contact stresses is currently indirectly accounted by using wheel load as a proxy for tire pressure. In most pavement design methods, the tire-pavement contact stress is assumed to be equal to the tire inflation pressure and uniformly distributed over a circular area. A methodology that explicitly accounts for the effect of tire inflation pressure and the corresponding contact stresses on pavement response and performance is currently lacking. This research evaluates the pavement responses of typical pavement structures under the combined actions of variable wheel loads and tire pressure. A multi-layer linear-elastic computer program, CIRCLY, was used to estimate the pavement responses under uniform constant stress and actual contact stress distributions. Three critical pavement responses were evaluated, including longitudinal and transverse tensile strains and compressive strains on the top of the subgrade. The differences of the strains estimated by the two models were statistically analyzed to quantify the effect of the assumption of uniform stress over a circular shape in most traditional pavement design approaches. The traditional model proved to be reliable for estimating the compressive strains on the top of the subgrade. The tensile strains at the bottom of the asphalt layer under actual contact stress, however, are quite different from those under uniform constant stress. Contrary to initial expectation, for the cases evaluated in this research, the assumption of uniform stresses is a conservative approach.

Keywords: Mechanistic-Empirical Design, Wheel Load, Tire Pressure, Pavement Response, Performance

ENTIRE REPORT (Adobe Acrobat File – 1.2 MB)

Driving by Choice or Necessity?

Lisa Weston and Susan Handy, University of Texas at Austin, January 2005, 89 pp. (167522-1)

From just about all accounts, Americans are driving more than ever, not just to work but to shopping, to school, to soccer practice and band practice, to visit family and friends, and so on. Americans also seem to be complaining more than ever about how much they drive – or, more accurately, how much everyone else drives. However, the available evidence suggests that a notable share of their driving is by choice rather than necessity. Although the distinction between choice and necessity is not always so clear, it is important for policy makers. For necessary trips, planners can explore ways of reducing the need for or length of the trip or ways of enhancing alternatives to driving. For travel by choice, the policy implications are much trickier and touch on basic concepts of freedom of choice. This paper first develops a framework for exploring the boundary between choice and necessity based on a categorization of potential reasons for and sources of “excess driving” and then uses in-depth one-on-one interviews guided by this framework to characterize patterns of excess driving. This research contributes to a deeper understanding of travel behavior and provides a basis for developing policy proposals directed at reducing the growth in driving.

Keywords: Excess Driving, Travel Behavior, Private Vehicle Trips, Traffic Congestion

ENTIRE REPORT (Adobe Acrobat File – 414 KB)

Feasibility Evaluation Model for Toll Highways

Rafael M. Aldrete Sanchez, Richard L. Tucker, B. Frank McCullough, University of Texas at Austin, January 2005, 302 pp. (467502-2)

This report describes the development of a Feasibility Evaluation Model for Toll Highways (FEMTH). FEMTH is a financial feasibility and risk analysis computer model developed to assess the degree of financial risk associated with a toll highway project in the pre-project planning stage. The model incorporates the use of simulation through a spreadsheet add-in that enables probabilistic risk analyses of the most important variables that affect the financial outcome of a toll highway project. The major contributions of this study are: (1) the development of a toll highway pre-project planning tool that integrates probabilistic risk analysis and simulation concepts that were not of practical use before into an affordable and easy to use computer model, and (2) a conceptual and mathematical representation of the major variables that affect the financial outcome of a toll highway project and their interaction.

Keywords: Feasibility Evaluation Model for Toll Highways, FEMTH, Toll Roads, BOT, Toll Traffic Demand Model, Toll Road Financial Analysis

ENTIRE REPORT (Adobe Acrobat File – 3.5 MB)

Identification of Vulnerable Transportation Infrastructure and Household Decision Making Under Emergency Evacuation Conditions

Pamela Murray-Tuite and Hani Mahmassani, University of Texas at Austin, January 2005, 203 pp. (167528-1)

This report combines two primary problems under general disaster considerations. First, a methodology is presented to identify vulnerable transportation infrastructure, which is defined as the set of network links, the damage of which results in the maximum disruption of the network’s origin-destination connectivity. The disrupting agent is permitted a limited number of resources with which to damage the network. The measure of disruption, resulting from the damage, is based on a given set of traffic conditions, the availability of alternate paths, and roadway design characteristics. A bi-level mathematical programming model represents the interaction of the traffic assignment and the disruption measure. This bi-level model allows the problem to be viewed as a game between an evil entity, who seeks to disrupt the network, and a traffic management agency that routes vehicles so as to avoid vulnerable links to the greatest degree possible while meeting origin-destination demands.

The second problem is to mathematically describe household decision making behavior in an emergency evacuation. Traditional transportation network evacuation models have omitted a commonly observed sociological phenomenon – that families gather together before evacuating an area. This omission can lead to overly optimistic evacuation times, and the evacuation models fail to capture underlying traffic patterns that only arise during times of crises. Two linear integer programs are developed to model the decision making behavior; the first describes a meeting location selection process and the second assigns trip chains for drivers to pick up family members who may not have access to a vehicle. The mathematical programs are combined with a traffic assignment-simulation package for evacuation analysis.

Interactions between the two problems are also explored. Evacuation conditions are examined when the traffic management agency routes traffic around vulnerable links. The impact of the unusual traffic patterns, that arise using the household decision making behavior evacuation model, is evaluated in terms of shifts in the relative vulnerability of the transportation links. Finally, the routing strategies are evaluated for extensions in network evacuation times.

Keywords: Vulnerable Transportation Structures, Evacuation Modeling, Disaster Management, Transportation Strategy Evaluation, Emergency Evacuation

ENTIRE REPORT (Adobe Acrobat File – 1 MB)

Freight Data Needs at the Metropolitan Level and the Suitability of Intelligent Transportation Systems in Supplying MPOs with the Needed Freight Data

Isabel C. Victoria and C. Michael Walton, University of Texas at Austin, December 2004, 173 pp. (167247-1)

Many Metropolitan Planning Organizations (MPOs) have identified the lack of robust and accurate freight data as a major constraint in conducting meaningful freight planning. An in-depth literature review was conducted that covered (1) the most relevant freight issues faced by MPOs, (2) the state-of-the-art methodologies used in urban travel demand forecasting to integrate the passenger and freight components, (3) primary and secondary freight data sources and their strengths and limitations for supporting urban planning activities, and (4) the full spectrum of Intelligent Transportation Systems (ITS) technologies that are considered rich sources of freight data. A Freight Data Needs Survey was administered to U.S. MPOs to assess urban freight data needs given the demographic characteristics of the region, the freight issues MPOs have to deal with, the state-of-the-practice in integrating the freight component into the urban travel demand models (TDMs), freight collection activities at the metropolitan region, the level of deployment of ITS technologies, and the use of archived ITS data to support urban planning activities. Special emphasis was given to cargo data, freight transportation modes data, and terminal/intermodal transfer facilities data because they provide valuable insight into urban freight movements. The results of the survey revealed that, although two-thirds of the responding MPOs are conducting freight planning, only 26% of them have integrated both the passenger and freight components into their TDMs. Among the responding MPOs, 49% to 94% indicated a need for origin-destination patterns, routing details, shipment details, and commodity type information, while cargo data availability varied from 6% to 46%. The percentage of respondents who indicated a need for highway/truck data, rail data, air data, and water data varied between 51% and 100%, while transportation mode data availability ranged between 0% and 40%. Finally, the percentage of respondents who indicated a need for terminal/intermodal transfer facilities data varied between 82% and 97%, while the availability of this data varied from 3% to 18%. These figures point to the substantial need for freight data, especially among the small, mid-size, and mid-large MPOs. It is thus obvious that effective freight planning and wholly informed decisions are still largely limited by a lack of reliable data. Given a lack of funding sources, primary data collection is also not an option for many small to mid-large MPOs. For the future, these MPOs will have to explore innovative and cost effective means to gather an understanding of freight movements. This study showed that data collected by electronic means such as those provided by ITS can be invaluable to urban freight planning.

Keywords: Metropolitan Planning Organizations, Urban Freight Data Needs, Urban Freight Data Available, Freight Collection Methods, ITS Freight Data, Passenger and Freight Components, Urban Travel Demand Models

ENTIRE REPORT (Adobe Acrobat File – 946 KB)

Analyze the Impact of Traffic on Air Quality and Select Appropriate ITS Strategies for Emissions Mitigation

Zhong Wang and C. Michael Walton, University of Texas at Austin, November 2004, 96 pp. (167829-1)

This report presents a framework for analyzing the air quality impact of transportation sector and selecting appropriate Intelligent Transportation Systems (ITS) strategies to reduce mobile source emissions. First within a GIS framework, the mobile source emissions are estimated on the basis of vehicle fleet composition, emission factors and traffic characteristics. Then, a concise four-step method is proposed to select ITS strategies to reduce traffic emissions according to the Federal Highway Administration (FHWA) ITS planning process version 2.1. Following the four-step method, the appropriate ITS strategies can be identified and their potential benefits and impact can be evaluated. In this study, the emission problems are defined based on the emissions modeling within a GIS framework. The ITS strategies are screened under the guidance of the National ITS Architecture. The identified ITS strategies are evaluated by doing experiments with ITS Deployment Analysis System (IDAS). A case study was performed in Austin, TX. It shows that the proposed emissions modeling method and the ITS strategy selection method is very helpful for regional ITS planning and evaluation. The methods and results from this report will be very useful for decision-makings in ITS investments and deployments.

Keywords: Air Quality, Emissions, Geographic Information System (GIS), Intelligent Transportation Systems (ITS), ITS Evaluation, ITS Planning, Incident Management System

ENTIRE REPORT (Adobe Acrobat File – 1.3 MB)

An Exploratory Analysis of Weekend Activity Patterns in the San Francisco Bay Area

Allison M. Lockwood, Sivaramakrishnan Srinivasan, and Chandra R. Bhat, University of Texas at Austin, November 2004, 38 pp. (167820-1)

Research on travel-demand modeling has predominantly focused on weekday activity-travel patterns, with the study of the effects of commute travel on peak period traffic congestion as a major objective. In contrast, there have been few studies examining the weekend activity-travel behavior of individuals. However, weekend travel volume has been increasing over time and is comparable to weekday travel volumes. Hence, weekend activity-travel patterns warrant careful attention in transportation planning.

The focus of this report is to present a comprehensive exploratory analysis of weekend activity-travel patterns and to contrast weekday and weekend activity participation characteristics. Data from the 2000 San Francisco Bay Area Travel Survey are used in the analysis. A comparative analysis of several aggregate activity-travel characteristics indicates that, while the weekday and weekend travel volumes are comparable, there are several key differences in activity-travel characteristics. Specifically, weekend activity-travel is found to be predominantly leisure oriented and undertaken during the mid-day period. The average trip distances are longer during the weekends. The transit shares are lower but the occupancy levels in personal automobiles are higher during the weekends. The weekend activity sequencing and trip-chaining characteristics explored in this study provide further insights into individuals’ activity organization patterns on weekend days.

In the overall, this report highlights the importance of studying weekend activity-travel behavior for transportation planning and air-quality modeling. Insights from this exploratory analysis can form the basis for comprehensive weekend activity-travel modeling efforts.

Keywords: Weekend Activity-Travel Characteristics, PMT and VMT By Trip Purpose, Activity-Episode Sequencing, Trip Chaining, Exploratory Analysis

ENTIRE REPORT (Adobe Acrobat File – 281 KBytes)

Framework for ITS Deployments to Enhance Highway Safety

Arnab K. Gupta and C. Michael Walton, University of Texas at Austin, October 2004, 84 pp. (167828-1)

The operational efficiency of a transportation system is greatly limited by incidents which result in great economic losses. In this research a framework for deployment of ITS applications is developed that will ensure effective management of incidents. The study focuses on improving safety of the access controlled highways using such deployments. A decision making methodology called ELECTRE I is used for selecting the best deployment strategy. The different alternative strategies are evaluated using new software tools such as ITS Deployment Analysis System (IDAS) in conjunction with spatial analysis and Highway Capacity Manual procedures to develop an overall benefits evaluation strategy that synthesizes both operational and economic benefits of different Incident Management strategies.

Keywords: Intelligent Transportation Systems, ITS, Safety, IDAS, Deployment Strategy

ENTIRE REPORT (Adobe Acrobat File – 1 MB)

Potential Application of ITS Technologies to Improve Commercial Vehicle Operations, Enforcement, and Monitoring

Alison Conway and C. Michael Walton, University of Texas at Austin, October 2004, 49 pp. (473700-00069-1)

This report examines the potential for implementing new technologies to improve upon current practices for truck weight enforcement and commercial vehicle management in the United States. As truck freight traffic continues to grow, expansion of the existing network alone will not accommodate traffic flows. It will be necessary for government to introduce new technologies and legislation to maintain sufficient flow. Various technologies already in use throughout Europe and North America for weight and credential enforcement, toll collection, and fleet management offer potential for improved traffic flow and potential solutions to future congestion, financial constraints, and environmental concerns. This report provides a review of these technologies, and the potential benefits of implementing these systems in the US. The review focuses on the state of Texas, which is an important NAFTA corridor that currently utilizes traditional static, semi-portable, and portable scales and fixed price permits for commercial vehicle enforcement.

Keywords: Commercial Vehicle Enforcement, Commercial Vehicle Operations (CVO), ITS, On-board Monitoring, On-board Weighing, Toll Collection Technologies, Virtual Weigh Stations, Weigh-In-Motion (WIM)

ENTIRE REPORT (Adobe Acrobat File – 300 KB)

Policy and Financial Analysis of High-Speed Rail Ventures in the State of Texas

Craig E. Roco and Leslie E. Olson, Texas A&M University, September 2004, 89 pp. (167150-1)

A renewed interest in high-speed rail as an alternative transportation mode in Texas remains mostly as an idea, with opinions based primarily on perceptions about the state’s past experience with this technology. If this concept is to advance toward a realistic alternative for transportation planners, future policies should be formulated with consideration of past policies, corporate behavior, forecasting reliability, and financial feasibility. Therefore, previous public and private efforts to bring high-speed rail to Texas have been investigated with the hope that future ventures will be timely, cost effective, and reliable. This report presents an alternative feasibility assessment methodology to assist in achieving these goals.

Keywords: High-Speed Rail Policy, Transportation Economics, Feasibility Analysis Methodology, Texas TGV Consortium, Texas High-Speed Rail Franchise

ENTIRE REPORT (Adobe Acrobat File – 633 KB)

Road Pricing Simulations: Traffic, Land Use and Welfare Impacts

Surabhi Gupta, Sukumar Kalmanje and Kara Kockelman, University of Texas at Austin, September 2004, 33 pp. (167242-1)

This work explores the traffic, land use and welfare impacts of road pricing in the Austin region, applying tolls to existing bridges, instituting a tolled cordon around the downtown area, and introducing planned toll roads. Different toll scenarios are examined, including fixed versus variable tolling, and tolls based on time of day, traffic, and travel distance. Austin-calibrated DRAM-EMPAL models are used to predict the future residential and work location distribution. Land use model outputs are used in a four-step travel demand model (TDM), and the resulting travel times are fed back into the TDM as needed, in order to obtain converged results. Joint mode and time of day choice models and multinomial destination choice models are used. The results include, traffic redistribution over time and space, location choice changes in the long term, and traveler welfare implications. In summary, the newly proposed toll roads in Austin are revenue generating and welfare improving. Bridge tolls would be successful in redistributing traffic, while the downtown appears highly sensitive to cordon tolls, which would be hard on commuters.

Keywords: Road Pricing, Application, ITLUM

ENTIRE REPORT (Adobe Acrobat File – 443 KB)

Identifying Gaps and Limitations in Data Sources by Mapping the Transportation Chain of International Trade Shipments at U.S. Ports

Leigh Boske, Abhay Kantak and Stephen Spruiell, University of Texas at Austin, September 2004, 57 pp. (167241-1)

According to the Transportation Research Board, from 1990 to 2001, the value of U.S. international merchandise trade more than doubled (in inflation-adjusted dollars), from $891 billion to over $2 trillion. Also, during this period, the value of U.S. merchandise trade grew at an average annual rate of 8 percent, while growth in U.S. real gross domestic product (GDP) averaged 3 percent per year. Further, more than 10 percent of the 16 billion tons of freight moved on the nation’s transportation system is international freight, either entering the country as imports or intended for export. The increasing pace of globalization and the differential in manufacturing costs between the U.S and developing countries like China will mean that trade, and more particularly imports, will continue to grow in the foreseeable future. Despite the growing importance of international trade in the U.S. economy, existing data sources do not provide any transportation data on the domestic portion of import shipments. This report, while profiling existing data sources, makes an attempt to map the transportation chain of international trade shipments using profiled data sources and thus identifies data gaps and limitations in mapping that chain.

Keywords: Gaps and Limitations in Data Sources, Mapping the Transportation Chain, International Trade Shipments

ENTIRE REPORT (Adobe Acrobat File – 304 KB)

Compendium: Papers on Advanced Surface Transportation Systems, 2004

Texas A&M University, August 2004, 315 pp. (473700-00003-8)

This document is the culmination of the fourteenth offering of a Mentors Program at Texas A&M University on Advanced Surface Transportation Systems which was presented in 2004 by the Advanced Institute in Transportation Systems Operations and Management. The Program allows participants to work closely with recognized experts in the field of intelligent transportation systems (ITS) and traffic operations and management. The highly successful Mentors Program has been available to transportation engineering graduate students at Texas A&M University since 1991. In 2004, the Program was available to state Department of Transportation employees as well.

As part of the Mentors Program six top-level transportation professionals from private enterprise and departments of transportation, were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems in early June. Immediately following the Symposium, the participants enrolled in the Program took part in a Forum and a Workshop with the invited mentors and the course instructor. Each participant held numerous discussions with the mentors and course instructor to identify a topic area for a paper. The state DOT participants selected topics that had direct application to the needs of their respective states. Each participant worked with his/her mentor and course instructor to finalize a topic area and objectives for a paper. In addition to discussions with the course instructor, the participants (communicating via telephone, e-mail, fax and mail) worked directly with the mentors throughout the summer while preparing their papers. The mentors and the state DOT employee participants returned to the Texas A&M University campus in late July for formal presentations of the papers.

Keywords: Intelligent Transportation Systems, Advanced Traffic Management Systems, Traffic Management Centers, Homeland Security, Incident Management, Planned Special Events, Signalization, Metering, Roundabouts, Road User Fees, Freeway Service Patrols, Highway Performance Measures Accelerated Construction, Internet

REPORT PREFACE AND TABLE OF CONTENTS (Adobe Acrobat File – 8.7 MB)

Analysis of Start-Up Cross-Gulf Sea Shipping Activities with Mexico Since 1990: Problems and Opportunities

C. James Kruse, David H. Bierling and Nathan J. Vajdos, Texas A&M University, August 2004, 82 pp. (473700-00021-1)

At the same time that traffic congestion is increasing on our nation’s highways, international trade continues to show strong growth trends, especially NAFTA trade between the U.S. and Mexico. Because of this, much interest has surfaced in “short sea shipping,” loosely defined as sea shipping that does not involve more than one continent. This report looks at what has been attempted since 1990 in one subset of short sea shipping-U.S.-Mexico cross-Gulf services. The objective of the report is to determine what services have been attempted, what obstacles they encountered, and what policies might be implemented to encourage the success of future ventures. This was done through extensive literature searches, interviews with participants in previous ventures, and surveys and discussions with port authorities. In order to provide context for the study, a description of the U.S. Gulf and Mexican port systems is included along with brief summaries of each of the ports identified as being actively involved in the trade. Topics for further research are also identified.

Keywords: NAFTA, Gulf of Mexico, Port, Ports, Shipping, Short Sea, Short Sea Shipping, Venture, Commodity, Trade, Transportation, Congestion, Cargo, Business, Research, Gulf Ports, Commerce, Shipping Services, Shipping Companies, Shipping Ventures

ENTIRE REPORT (Adobe Acrobat File – 464 KB)

3D Visualization as a Tool to Evaluate Sign Comprehension

Susan T. Chrysler, James Wright and Alicia Williams, Texas A&M University, August 2004, 64 pp. (167721-1)

Past research assessing sign comprehension has often employed methodologies such as simple, self-paced paper and pencil tests that ask “what do you think this sign means?” These studies often fail to detect any improvement in comprehension from one sign to another, newly designed version of the same sign. This experiment evaluated the effectiveness of different display methods to assess traffic sign comprehension. While a driving simulator allows fine measurements of driving performance, it is an expensive and inconvenient way to present signs for a simple multiple choice comprehension test. One of the aims of this study was to identify less expensive and more portable methods of testing sign comprehension. Different sign designs were compared which indicated freeway-to-freeway splits, lane drop exits, and left exits. A sign comprehension test was administered via the following methods: 1) Self-paced paper and pencil test of images of signs in a road context; 2) Self-paced paper and pencil survey of images of signs in isolation; 3) Limited exposure time computer presentation of the signs in road context; 4) ) Limited exposure time computer presentation of the signs in isolation; 5) Video loop of a driving scene generated by driving simulator software presented in a classroom; and 6) Fully interactive driver-in-the-loop presentation of the signs in appropriate roadway scenes in a wrap-around simulator. Results showed that for simple bold messages, the time-limited presentation media all performed similarly. The video presentation seemed to suffer some clarity reduction for text-heavy guide signs. The self-paced paper tests, as used in much previous work, showed higher comprehension scores for certain sign types.

Keywords: Traffic Sign Comprehension, Driving Simulator, Sign Understanding, Test Methodology

ENTIRE REPORT (Adobe Acrobat File – 1.2 MB)

Compendium of Student Papers: 2004 Undergraduate Transportation Engineering Fellows Program

Steven D. Schrock, editor, Texas A&M University, August 2004, 375 pp. (473700-00003-9)

This report is a compilation of research papers written by students participating in the 2004 Undergraduate Transportation Engineering Fellows Program. The ten-week summer program, now in its fourteenth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participation in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or Texas Transportation Institute researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) the impacts of night construction on crash likelihood; 2) the alleviation of congestion on the Katy Freeway through economic incentives; 3) the setting of detection zones for transit signal priority; 4) the improvement of planning-level speed estimation models; 5) the analysis of QuickRide users and nonusers; 6) the analysis of reading time and comprehension of simulated dynamic message sign messages; 7) the validation of video-based speed measurements; 8) the development of worksite criteria for “floating” speed zone research; 9) the comparison of erratic traffic behavior at congested daytime and nighttime work zones; 10) the investigation of issues regarding managed lane interoperability; 11) the evaluation of the effectiveness of dual portable changeable message signs in the display of a single message; 12) the evaluation of horizontal signing applications; and 13) the evaluation of red border speed limit signs.

Keywords: Work Zones, Toll Roads, Transit Signal Priority, Speed Estimation Models, CMS Reading Time, Video-Based Speed Measurement, Managed Lanes, Dual Portable Changeable Message Signs, Horizontal Signing, Red Border Speed Limit Signs

ENTIRE REPORT (Adobe Acrobat File – 11.3 MB)

Developing a Sketch-Planning Technique Relating Economic Activity and Urban Mobility in Small and Medium-Sized Urban Areas

David L. Schrank, Texas A&M University, August 2004, 366 pp. (167703-1)

Traffic congestion continues to be a growing problem for cities of all sizes in the United States. Transportation agencies in urban areas are facing the difficult challenges of providing an efficient and reliable transportation system for residents and businesses despite ever-diminishing resources. Agencies in these areas need the capability of determining the future benefits of transportation investments so they can communicate this information to the public. This capability is difficult for many agencies, especially some of the smaller ones, who may not have the resources to make these analyses without turning to expensive long-range models.

This research uses readily available socio-economic, land use, and traffic congestion data from many of the Texas urban areas to create prediction models to estimate future traffic congestion levels. Many of the transportation agencies that could utilize this tool do not have the resources to deal with large complex databases. Thus, basic information such as income, employment, single family residences, or commercial properties, to name a few, is used to create the predictions models. Results from this research show that traffic congestion prediction models can be created from socio-economic and land use data. These models were created for eighteen individual Texas urban areas and several combinations of areas. Transportation agencies could use the results of this research to estimate future congestion in their respective areas.

Keywords: Urban Mobility, Traffic Congestion, Congestion Management, Land Use Planning

ENTIRE REPORT (Adobe Acrobat File – 989 KB)

 

Development and Evaluation of a Framework for Selecting Operational Strategies for an Integrated Diamond Interchange – Ramp Metering Control System

Zong Tian and Kevin Balke, Texas A&M University, August 2004, 75 pp. (473700-00025-1)

Diamond interchanges and their associated ramps are where the surface street arterial system and the freeway system interface. Historically, these two elements of the system have been operated with little or no coordination between the two. One drawback of operating the ramp-metering system and the diamond interchange system in isolation is that traffic from the ramp, particularly if it is metered, can spill back into the diamond interchange, causing both congestion and safety concerns at the diamond interchange. While flushing the ramp queues by temporarily suspending ramp metering has been the primary strategy for preventing queue spillback, it can result in freeway system breakdown, which would affect the entire system’s efficiency.

The aim of this research was to develop operational strategies for managing an integrated diamond interchange ramp-metering system (IDIRMS), and to develop a general framework for implementing such an integrated system. Integrated control strategies (ICS) were developed based on the two commonly used diamond interchange phasing schemes, basic three-phase and TTI four-phase. The ICS were evaluated using VISSIM microscopic simulation under three general traffic demand scenarios: low, medium, and high, as characterized by the volume-to-capacity ratios at the metered ramps. Preliminary system design and detailed functional diagrams were developed to guide traffic engineers for field implementation of the system.

The results of the evaluation indicated that the integrated operations through an adaptive signal control system were most effective under the medium traffic demand scenario by preventing or delaying the onset of ramp-metering queue flush, thereby minimizing freeway breakdown and system delays. The integrated system would require enhanced detection and communication systems, but the system could be designed and implemented based on existing features equipped with most advanced traffic signal controllers.

Keywords: Diamond Interchange, Ramp Metering, Integration, IDIRMS, ICS, Simulation

ENTIRE REPORT (Adobe Acrobat File – 2.6 MB)

Development and Validation of a Flexible, Open Architecture, Transportation Simulation with an Adaptive Control Implementation

Michael Hunter and Randy B. Machemehl, University of Texas at Austin, June 2004, 276 pp. (167823-1)

Simulation has been utilized in the planning and development of almost all sectors of the transportation field. The practicing transportation community primarily relies on simulation packages. When a practitioner (or end user) uses a simulation package, most of the simulation development efforts have already been completed. Unfortunately, the use of these simulation packages has several disadvantages, most notably the “black box” phenomenon and reduced modeling flexibility.

The simulation model described in this research lays the foundation for a transportation simulation, OPEN-TS3, that minimizes the black box problem and increases modeling flexibility, while still providing an easy to use package in which highly capable models may be quickly and accurately built. The approach to simulation in this research is to develop a platform that allows for the use of existing constructs where applicable, while still retaining the flexibility for the user to incorporate new basic modeling constructs. OPEN-TS3 utilizes SIMAN (a simulation language) and ARENA (a simulation development tool), both commonly found in manufacturing applications.

In intersection and arterial validation studies, comparing the OPEN-TS3 to CORSIM, a high level of agreement was seen in the volumes, delays, queues, and speeds simulated by both models. Some differences were seen between the models in overcapacity demand situations, most significantly in left turn operations. Agreement was also seen in a comparison to real-world delays measured for a twelve-intersection downtown Chicago network. The real-world data validation effort also highlighted some important issues regarding validation with real-world data, in particular the difficulties in obtaining data and the potential pitfalls of GPS probe vehicle studies.

As a demonstration of the flexibility of OPEN-TS3 two adaptive signal control strategies are also successfully implemented. The adaptive control strategies are tested on three different networks under varying volume conditions. Based on the OPEN-TS3 simulations it was seen that adaptive control can provide superior overall performance, but can have a significantly greater range of variability than that of pre-timed control.

Keywords: Simulation, Validation, Adaptive Control

ENTIRE REPORT (Adobe Acrobat File – 7 MB)

Optimal Transit Route Network Design Problem: Algorithms, Implementations, and Numerical Results

Wei Fan and Randy B. Machemehl, University of Texas at Austin, May 2004, 267 pp. (167244-1)

Previous approaches used to solve the transit route network design problem (TRNDP) can be classified into three categories: 1) Practical guidelines and ad hoc procedures; 2) Analytical optimization models for idealized situations; and 3) Meta-heuristic approaches for more practical problems. When the TRNDP is solved for a network of realistic size in which many parameters need to be determined, it is a combinatorial and NP-hard problem in nature and several sources of non-linearities and non-convexities involved preclude guaranteed globally optimal solution algorithms. As a result, the meta-heuristic approaches, which are able to pursue reasonably good local (possibly global) optimal solutions and deal with simultaneous design of the transit route network and determination of its associated service frequencies, become necessary.

The objective of this research is to systematically study the optimal TRNDP using hybrid heuristic algorithms at the distribution node level without aggregating the travel demand zones into a single node. A multi-objective nonlinear mixed integer model is formulated for the TRNDP. The proposed solution framework consists of three main components: an Initial Candidate Route Set Generation Procedure (ICRSGP) that generates all feasible routes incorporating practical bus transit industry guidelines; a Network Analysis Procedure (NAP) that determines transit trips for the TRNDP with variable demand, assigns these transit trips, determines service frequencies and computes performance measures; and a Heuristic Search Procedure (HSP) that guides the search techniques. Five heuristic algorithms, including the genetic algorithm, local search, simulated annealing, random search and tabu search, are employed as the solution methods for finding an optimal set of routes from the huge solution space. For the TRNDP with small network, the exhaustive search method is also used as a benchmark to examine the efficiency and measure the quality of the solutions obtained by using these heuristic algorithms.

Several C++ program codes are developed to implement these algorithms for the TRNDP both with fixed and variable transit demand. Comprehensive experimental networks are used and successfully tested. Sensitivity analyses for each algorithm are conducted and model comparisons are performed. Numerical results are presented and the multi-objective decision making nature of the TRNDP is explored. Related characteristics underlying the TRNDP are identified, inherent tradeoffs are described and the redesign of the existing transit network is also discussed.

Keywords: Transit, Route, Network Design, Multi-objective Decision Making, Heuristic Search, Genetic Algorithm, Local Search, Simulated Annealing, Tabu Search, Random Search, Exhaustive Search, Network Analysis, Headway, Transfer, Long-walk

ENTIRE REPORT (Adobe Acrobat File – 1.8 MB)

Correlates of Environmental Constructs and Perceived Safety Enhancements in Pedestrian Corridors Adjacent to Urban Streets

Byoung-Suk Kweon, Jody Rosenblatt Naderi, Praveen Maghelal and Woo-Hwa Shin, Texas A&M University, April 2004, 91 pp. (167722-1)

Motivated by growing national health concerns related to early onset of obesity and obesity related diseases, the research team asked parents of young children to describe the ideal street where their child could develop the habit of walking, as well as connecting with the earth, and themselves.

A multi-ethnic, multi-monied focus group made up of participants from elementary schools in the twin cities were asked about perceptions of safety as it related to allowing their children to walk to school. Researchers then developed and tested the findings in two modalities:

1) A platform for “clinically” testing the perception of safety. This platform was a 3-dimensional interactive street environment that could be affected by alterations in the physical construct of the environment; the interactive street environment was constructed according to focus group findings.
2) A measure describing the physical constructs of the walking environment on residential streets, defined as significant by the focus groups.

Researchers examined the following questions:

1) Do different streetscapes influence parent’s perception of safety?
2)Does lateral separation from the vehicular travel-way influence whether a parent will allow their child to walk to school?
3) How are perceptions of safety and spatial edge related to each other?
4) Are there consistencies in the way people measure and describe the walking environment in the field?

The results from the trials on-site and in the simulation laboratory suggest that people do perceive different levels of safety when the physical environment is altered and that this perception affects feelings about allowing their children to walk to school. Lateral separation from the traffic with a green buffer had a significant positive effect on perception that the sidewalk was safe for their children. However the decision to allow the child to walk or not is not based solely on the physical characteristic of the environment; economic and social reasons are important determinants as well.

Keywords: Pedestrian Environments and Safety, Landscape Urban Design and Health, Pedestrian Simulation, Context Sensitive Design, Children and School Pedestrian Environments

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Evaluation of the Air Quality and Noise Impacts of Regional Jet Service at Commercial Airports Serving Small Cities in Texas

Jeffrey D. Borowiec and L.D. White, Texas A&M University, March 2004, 81 pp. (167121-1)

Commercial airline passenger service in small markets is entering a phase that has the potential to change the industry in ways not seen since airline deregulation. The initiation of regional jet service to and from communities that previously had limited commercial service opens up a wide range of opportunities that support economic growth and trade for many communities as service levels increase and new city pairs are introduced. Along with the opportunities, however, have come a new set of high profile environmental issues that, until now, small cities have not had to deal with. These are primarily aircraft noise and exhaust emissions from arriving and departing aircraft but also include emissions from ground support equipment (GSE) and vehicles accessing the airport.

In this research, a base year reflecting the current use of turbo-prop aircraft was developed. Fleet mixes for the forecasted years were developed using the appropriate operations and enplanement forecasts. The analysis included two fleet mixes, one representing the existing turbo-prop aircraft and one representing the regional jet aircraft. Noise and air quality impacts were then measured using FAA approved and recommended software analysis tools.

For the noise analysis, the all regional jet fleet mix when compared to the existing fleet mix further reduced noise exposure impacts at the 55 dB level for eight of the 10 airports. In the air quality analysis, the regional jet fleet mix resulted in lower pollutant levels than the existing fleet mix for 2007 at many of the airports studied. Specifically, the regional jets resulted in lower CO levels at all ten airports, lower HC levels at eight of the ten airports, Lower NOX levels at six airports, lower SOX levels at five of the airports, and lower PM10 levels at all ten airports. In many of the instances where regional jet fleets did not decrease noise and emissions levels, they were not substantially higher than the existing fleet mixes that were used.

Keywords: Regional Jet, Airport Air Quality, Airport Noise, Regional Airline, and Small Community Air Service

ENTIRE REPORT (Adobe Acrobat File – 1.4 MB)

Potential for Reduced Greenhouse Gas Emissions in Texas Through the Use of High Volume Fly Ash Concrete

Cindy Estakhri, Don Saylak and Saleel D. Mohidekar, Texas A&M University, March 2004, 92 pp. (167709-1)

The objective of this study was to determine the potential for reductions in carbon dioxide emissions in Texas by substituting high volumes of fly ash in concrete production and to identify the resulting benefits and challenges.

Researchers reviewed the literature and determined that high volume fly ash (HVFA) can improve the properties of both the fresh and hardened concrete. It can improve workability, heat of hydration, strength, permeability, and resistance to chemical attack. A laboratory investigation was performed to investigate the potential of HVFA concrete in mitigating the effects of alkali-silica reactivity, which was recently a serious concern in Texas. The laboratory study showed high volumes of Class F ash are very effective in reducing the alkali-silica reaction from a potentially reactive state to an innocuous state.

Researchers compiled data for 18 power plants located throughout Texas and determined that a total of 6.6 million tons of fly ash are produced annually in Texas and about 2.7 million tons (or 40%) are generally sold for use in concrete or other end products. Researchers estimated production of concrete in Texas and determined that if 60 percent of the portland cement used in Texas concrete production were replaced with fly ash, carbon dioxide emissions could potentially be reduced by 6.6 million tons annually by the year 2015.

More education is needed for design engineers and for the concrete industry regarding the performance and environmental benefits which can be realized through increased use of fly ash in concrete.

Keywords: Concrete, Coal Combustion By-Products, Fly Ash, High-Volume Fly Ash Concrete, Alkali-Silica Reactivity, Carbon Dioxide Emissions, Highway Construction

ENTIRE REPORT (Adobe Acrobat File – 461 KB)

Transit-Oriented Development Workshop: Synthesis

Carol A. Lewis, Texas Southern University, January 2004, 45 pp. (473700-00044-1)

There is growing consensus about the need to be more proactive in decision making in regards to better coordinating public and private resources. One component in this way of thinking is to pursue more coordination of transit and land use under a concept termed, transit-oriented development (TOD). TOD neighborhoods tend to encourage walking, are linked very well to transit for meeting needs inside and outside of the neighborhood and provide a sense of place. The benefits of these neighborhoods are many, but include the fact that fewer automobiles are needed. Several communities are actively pursuing transit-oriented development. This report documents a TOD workshop where elements of planning, development and implementation of transit-focused communities were described. This work identifies several potential sites for transit-oriented development using Houston, Texas, as a case study. Both a bus and rail example are included.

Keywords: TOD, Transit-Oriented Communities, Sustainable Development, Livable Communities

ENTIRE REPORT (Adobe Acrobat File – 787 KB)

A Symposium Assessing the Concept of Regional Transportation Authorities: Application to Houston,Texas

Robert Hill and Carol A. Lewis, Texas Southern University, January 2004, 23 pp. (473700-00047-1)

The Houston metropolitan area is in the planning phases of determining if a multi-modal regional transportation authority is required to address the region’s mobility challenge. Various regions of the country are developing innovative ways to address their multi-modal transportation challenges. In the greater Houston area, there is a tremendous need for agencies, jurisdictions and all modes of transportation to collaborate on future projects in the region, known as “Regionalism”. The purpose of “Regionalism” is to facilitate liaisons between the region’s leadership, resources and citizens around a shared agenda for improving the economic vitality, the standard of living and quality of life in the region.

The purpose of this study is to assemble transportation professionals to address current transportation needs in light of new national transportation initiatives in the region. The establishment of collaboration between public agencies and private entities that are stakeholders in the Houston region’s transportation infrastructure and the creation of awareness of current and future transportation needs in the region will be discussed. The outlined objective was achieved by conducting: 1) a literature review to assess national initiatives on regionalism or regional cooperation and 2) a symposium, which attracted the area’ s transportation professionals to discuss questions.

Keywords: Regionalism, Multi-Modal, Regional Transportation Authorities

ENTIRE REPORT (Adobe Acrobat File – 169 KB)

Current and Future Rail Access Needs of Western Gulf – Texas Ports

David H. Biering, Curtis A. Morgan, Arthur P. James, Jeffery E. Warner, Gretchen A. Chabot, and Tim A. Sain, Texas A&M University, November 2003, 100 pp. (473700-00011-1)

A key element of a port’s viability and efficiency is its ability to distribute and receive cargo from its location to the inland area that it serves. This ability is largely affected by a port’s access to and from the hinterland provided by roadways, rail, and waterways. Use of particular transport modes at any individual port will depend on the transport networks that it is connected to, the markets that it serves, and the principal commodities that it handles. Access to and from mainlines is provided by branch lines and spurs, and these secondary connector lines are critical to providing optimal commodity movement capabilities. To identify potential deficiencies in port-rail access, the infrastructure along with current and projected levels of trade must be considered. This study is an evaluation of current and future rail access needs of key public deepwater ports along the Western Gulf – Texas Coast.

Keywords: Ports, Interconnections, Rail

ENTIRE REPORT (Adobe Acrobat File – 3.4 MB)

Sustainable Transportation Performance Measures for Developing Communities

Josias Zietsman, Laurence R. Rilett, and Seung-Jun Kim, Texas A&M University, October 2003, 165 pp. (167128-1)

The concepts of sustainable transportation can be implemented if they are clearly defined, quantified, and applied in the decision-making process. This study addressed these aspects for two test beds. The first is the Mabopane Centurion Development Corridor (MCDC) located in a developing nation (South Africa), the other one is the Houston corridor located in a developed nation (United States of America). An index for sustainable transportation was developed that is based on the multi-attribute utility theory (MAUT) technique. Various models were used to quantify the selected performance measures at both the aggregate (groups of vehicles) and disaggregate (individual vehicle) levels. These measures were then used to determine the index values for the individual links and the corridors as a whole. It was illustrated that the methodology proposed in this study allows for comparisons between corridors, irrespective of functional classification, overall goals, mode, analysis year, or even nations.

Keywords: Developing Nations, Sustainable Transportation, Performance Measures, Index, Decision Making

ENTIRE REPORT (Adobe Acrobat File – 859 KB)

A Parameterized Consideration Set Model for Airport Choice: An Application to the San Francisco Bay Area

Gozen Basar and Chandra Bhat, University of Texas at Austin, October 2003, 54 pp. (167520-1)

Airport choice is an important air travel-related decision in multiple airport regions. This report proposes the use of a probabilistic choice set multinomial logit (PCMNL) model for airport choice that generalizes the multinomial logit model used in all earlier airport choice studies. This study discusses the properties of the PCMNL model, and applies it to examine airport choice of business travelers residing in the San Francisco Bay Area. Substantive policy implications of the results are discussed. Overall, the results indicate that it is important to analyze the choice (consideration) set formation of travelers. Failure to recognize consideration effects of air travelers can lead to biased model parameters, misleading evaluation of the effects of policy action, and a diminished data fit.

Keywords: Air Travel, Metropolitan Area Planning, Discrete-Choice Models, Hazard Duration Models, Traveler Behavior

ENTIRE REPORT (Adobe Acrobat File – 382 KB)

Credit-Based Congestion Pricing: Travel, Land Value and Welfare Impacts

Kara M. Kockelman and Sukumar Kalmanje, University of Texas at Austin, October 2003, 34 pp. (167822-2)

This study explores the possible transportation and land-rent impacts of a new congestion management policy called credit-based congestion pricing (CBCP). Integrated land use-transportation models provide short- and long-term estimates of travel demand, network operations, location choice, and land use patterns. Using destination, mode and departure time choice models sensitive to changes in travel times and costs, household travel demands were simulated in order to appreciate the transportation effects of a CBCP policy for Austin, Texas. Changes in land use, locational accessibility and land rents as a result of CBCP also were simulated. Together, the transportation and land value benefits and costs The trip-based welfare impacts of such a policy were compared for three scenarios (full network pricing, major highway pricing only, and no pricing), in order to identify households and neighborhoods that will benefit most and least from such policies. The results corroborate prior results and hypotheses about the potential of a CBCP policy to alleviate congestion and generate benefits across the region income groups and traveler types.

Keywords: Credit-Based Congestion Pricing, Integrated Transportation-Land Use Models, Travel Demand Modeling, Transportation Policy

ENTIRE REPORT (Adobe Acrobat File – 206 KBytes)

Credit Based Congestion Pricing: A Policy Proposal and the Public’s Response

Kara M. Kockelman and Sukumar Kalmanje, University of Texas at Austin, October 2003, 34 pp. (167822-1)

Credit-based congestion pricing (CBCP) is a novel strategy proposed here. A revenue-neutral policy where road tolls are based on the negative externalities associated with driving under congested conditions, its generated tolls are returned to all licensed drivers in a uniform fashion, as a sort of driving “allowance”. Essentially, the “average” driver pays nothing, while frequent long-distance peak-period drivers subsidize others, in effect paying them to stay off congested roads. In order to anticipate initial public response to a CBCP policy, 500 individuals completed a detailed survey regarding perceptions of, and likely travel reactions to, such a policy. Weights were developed to correct for survey biases in gender, age and household income. Analytical results suggest that 25% support this new strategy, and support is strongly related to familiarity with the concept of congestion pricing. Respondent estimates of congested travel times to work or school almost double the uncongested times. Longer-term residents and retired people consider congestion to be more of an issue. Values of travel time vary greatly across respondents, as does trip flexibility. Those without children, younger respondents, and those with fewer vehicles appear more willing to support such a policy and more likely to modify their travel behaviors. The survey results corroborate the potential of a CBCP policy to alleviate congestion and generate benefits across income groups and traveler types.

Keywords: Credit-Based Congestion Pricing, Tolls, Peak-Period Driving

ENTIRE REPORT (Adobe Acrobat File – 164 KBytes)

A Guide to Conducting Business Along the Houston, Texas-San Antonio, Chile Trade Corridor

Leigh B. Boske and Carolina Freire Samudio, University of Texas at Austin, October 2003, 88 pp. (167821-2)

A Guide to Conducting Business along the Houston, Texas-San Antonio, Chile Trade Corridor describes both the logistics chain and steps that need to be taken to conduct business between the United States and Chile along the sea corridor joining the port of Houston, Texas and the port of San Antonio in Chile. To that end, the Guide is structured in three general sections. The first section provides an overview of Houston-San Antonio trade and describes the network of physical, commercial, and service infrastructure that exists in each port. The second section describes the logistics chain (southbound) along which goods move from the U.S. to Chile through the port of Houston, including a description of the steps involved in exporting to Chile as well as the actors and services involved. The third section describes the logistics chain (northbound) along which commodities are transported from Chile to the U.S. through the port of San Antonio including a description of the steps involved in importing into the United States. It specifies the actors, services, and requirements for importing in to the U.S. using the Houston-San Antonio, Chile trade corridor. The corridor study is especially relevant now that the United States and Chile have signed a free trade agreement which is expected to increase the volume of trade and investment between the two countries, especially via maritime. The final chapter of this Guide provides an overview of the recent U.S.-Chile free trade agreement.

Keywords: Trade Corridor, Transportation Corridor, Logistics, Texas-Chile Trade

ENTIRE REPORT (Adobe Acrobat File – 305 KBytes)

Public Transit and Livable Communities: Corpus Christi “After” Evaluation

Laura Higgins and Robin Rabinowitz, Texas A&M University, October 2003, 60 pp. (167422-1)

The Federal Transit Administration (FTA) has a major initiative underway focusing on using transit to enhance livable communities. The Corpus Christi Regional Transit Authority (RTA) received a Livable Community grant from the FTA in 1995. This grant has been used to make physical improvements around two of the RTA’s transit stations, located in a low income area of the city, and to develop additional social service programs to serve local residents. Assessing the impact of this project, as well as other FTA Livable Community projects throughout the country can provide a better understanding of the role transit can play in ensuring sustainable transportation systems. This research project examined the approaches taken by the RTA and by other Livable Community projects and the effects of those approaches on transit systems and the communities.

Keywords: Transit, Livable Communities Initiative, Urban Renewal

ENTIRE REPORT (Adobe Acrobat File – 1,026 KBytes)

A Guide to Conducting Business Along the Houston, Texas-Veracruz, Mexico Trade Corridor

Leigh B. Boske and Carolina Freire Samudio, University of Texas at Austin, October 2003, 79 pp. (167821-1)

Research on travel-demand modeling has predominantly focused on weekday activity-travel patterns, with the study of the effects of commute travel on peak period traffic congestion as a major objective. In contrast, there have been few studies examining the weekend activity-travel behavior of individuals. However, weekend travel volume has been increasing over time and is comparable to weekday travel volumes. Hence, weekend activity-travel patterns warrant careful attention in transportation planning.

The focus of this report is to present a comprehensive exploratory analysis of weekend activity-travel patterns and to contrast weekday and weekend activity participation characteristics. Data from the 2000 San Francisco Bay Area Travel Survey are used in the analysis. A comparative analysis of several aggregate activity-travel characteristics indicates that, while the weekday and weekend travel volumes are comparable, there are several key differences in activity-travel characteristics. Specifically, weekend activity-travel is found to be predominantly leisure oriented and undertaken during the mid-day period. The average trip distances are longer during the weekends. The transit shares are lower but the occupancy levels in personal automobiles are higher during the weekends. The weekend activity sequencing and trip-chaining characteristics explored in this study provide further insights into individuals’ activity organization patterns on weekend days.

In the overall, this report highlights the importance of studying weekend activity-travel behavior for transportation planning and air-quality modeling. Insights from this exploratory analysis can form the basis for comprehensive weekend activity-travel modeling efforts.

Keywords: Weekend Activity-Travel Characteristics, PMT and VMT By Trip Purpose, Activity-Episode Sequencing, Trip Chaining, Exploratory Analysis

ENTIRE REPORT (Adobe Acrobat File – 281 KBytes)

GIS-Based Assessment of Highway Network, Crash, and Traffic Volume Data in the Laredo-Nuevo Laredo Area

Cesar Quiroga, Robert Pina, and Michael Perez, Texas A&M University, October 2003, 74 pp. (167426-1)

The Texas-Mexico Border Region is undergoing extremely fast, radical changes, and it is critical for planners, engineers, and decision makers to develop a clear understanding of the various processes that drive, and are affected by, such growth. A number of government agencies are responsible for collecting and processing transportation-related data in the border region. Unfortunately, the available data tend to be scattered among various organizations and rarely include substantial amounts of information from the Mexican side of the border.

There is a need to provide an integrated approach to the issue of transportation data collection and analysis for the Texas-Mexico Border Region. This report describes a prototype geographic information system (GIS)-based framework for transportation data with a goal to better understand the characteristics of the transportation system along border areas. The report focuses on highway network data, crash data, and traffic volume data in the Laredo – Nuevo Laredo area. The report examines existing transportation data sources at various jurisdictional levels and evaluates the degree to which the data can be integrated. The report also summarizes an assessment of transportation data on the Mexican side of the border that resulted from a collaborative effort with the Instituto Mexicano del Transporte (IMT).

Keywords: Texas-Mexico Border, GIS, Transportation Data, Highway Network, Crash Data, Traffic Volumes, Databases

ENTIRE REPORT (Adobe Acrobat File – 1,672 KBytes)

Methodology for the Development of Binational Driver and Vehicle Databases

Mark Ojah and Juan C. Villa, Texas A&M University, September 2003, 78 pp. (167724-1)

The implementation of advaned transportation and trade information systems at the U.S.-Mexico border will confer benefits upon public and private sector stakeholders in both countries. But the ultimate success of these systems depends on their ability to deliver comprehensive and accurate information to authorized parties in a timely fashion. Much of this information will be sourced from existing databases that are planned for integration into broader frameworks. The persistence of information gaps and stakeholder disconnects underscores the need for a thorough review of existing information, and an assessment of outstanding data collection and integration needs. This research focuses on two of the most critical data elements in the border-crossing system, commercial driver and vehicle information. The study team identified potentially valuable tractor, trailer and driver data components not currently available or accessible to border stakeholders, and proposed how they might be integrated into overarching systems. The strategies presented enable the development of binational driver and vehicle databases that accelerate the processing of safe, legitimate trade, while establishing increasingly impermeable barriers to dangerous or illegal cross-border movements.

Keywords: Driver Data, Tractor Data, Trailer Data, NAFTA Trade Information, U.S.-Mexico Trucking, Border Data Processing, Commercial Vehicle Data

ENTIRE REPORT (Adobe Acrobat File – 337 KBytes)

Compendium of Student Papers: 2003 Undergraduate Transportation Engineering Fellows Program

Steven D. Schrock, editor, Texas A&M University, August 2003, 96 pp. (473700-00003-7)

This report is a compilation of research papers written by students participating in the 2003 Undergraduate Transportation Engineering Fellows Program. The ten-week summer program, now in its twelfth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participation in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or TTI researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) improving Houston QuickRide through an investigation of former users; 2) predicted driver response to a cordon toll around Fort Myers Beach, Florida; 3) quantitative analysis of the amount and types of nighttime work in the Waco and Austin districts; and 4) assessment of delay of transit buses in arterial systems.

Keywords: Transportation Improvement Strategies, Electronic Toll Collection, Cordon Tolling, Nighttime Work Zones, Transit Delay

ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)

Compendium: Papers on Advanced Surface Transportation Systems, 2003

Texas A&M University, August 2003, 368 pp. (473700-00003-6)

This document is the culmination of the fourteenth offering of a Mentors Program at Texas A&M University on Advanced Surface Transportation Systems which was presented in 2003 by the Advanced Institute in Transportation Systems Operations and Management. The Program allows participants to work closely with recognized experts in the field of intelligent transportation systems (ITS) and traffic operations and management. The highly successful Mentors Program has been available to transportation engineering graduate students at Texas A&M University since 1991. In 2003, the Program was available to state Department of Transportation employees as well.

As part of the Mentors Program six top-level transportation professionals from private enterprise and departments of transportation, were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems in early June. Immediately following the Symposium, the participants enrolled in the Program took part in a Forum and a Workshop with the invited mentors and the course instructor. Each participant held numerous discussions with the mentors and course instructor to identify a topic area for a paper. The state DOT participants selected topics that had direct application to the needs of their respective states. Each participant worked with his/her mentor and course instructor to finalize a topic area and objectives for a paper. In addition to discussions with the course instructor, the participants (communicating via telephone, e-mail, fax and mail) worked directly with the mentors throughout the summer while preparing their papers. The mentors and the state DOT employee participants returned to the Texas A&M University campus in early August for formal presentations of the papers.

Keywords: Intelligent Transportation Systems, Advanced Traffic Management Systems, Traffic Management Centers, Homeland Security, Incident Management, Inter-Modal Freight Distribution, Freeway Work Zones, Pedestrian Crossings, Remote Sensing, Mobile Source Emission Models, Adverse Weather Information, Transportation Funding, Roundabouts

REPORT PREFACE AND TABLE OF CONTENTS (Adobe Acrobat File – 9.2 MB)

Impact of New Large Aircraft on Passenger Flows at International Airport Terminals

Chiung-Yu Chiu and C. Michael Walton, University of Texas at Austin, July 2003, 201 pp. (167530-1)

The development of New Large Aircraft (NLA) has been a topic of considerable interest and speculation. The first generation of the NLA with 555-seat capacity will presumably be entering into commercial service by 2006. Due to the greater dimensions of the NLA and more simultaneous arriving passengers, there will be substantial impacts on existing airports after its launch. Terminal operations, particularly individual passenger processing facilities, will be one of the significantly affected components of the entire airport system. The analysis of these impacts on individual terminal facilities, which will be strongly influenced, have been lacking because of the uncertain characteristics of NLA operations. Therefore, a method that is capable of investigating the impact of the NLA under such uncertainty is needed for airport operators to determine the potential effects and to accommodate the possible required changes in terminal facilities.

This report proposes an integrated simulation method to investigate the potential impacts on the operation performance of primary processing facilities. The method utilizes scenario analysis in a before and after context, and attempts to analyze the impacts under current uncertainty regarding the operating characteristics of the NLA and its market share. This study focuses on analyzing the impacts on international arriving passengers. The arriving passenger flow is modeled as a queuing network system in this study, comprised of a series of passenger processing facilities. The derivation of arrival and service probability distributions in the simulation model are based on a survey of international airports and by observational data collected at selected international terminals. The simulation model can be used to examine the potential bottlenecks in the arriving passenger flow and to evaluate the operational strategies. Major impacts at the baggage claim system are detected in the simulation model, and the related strategies of increasing baggage processing capacity are thus evaluated. The results obtained from impact analyses and the evaluation of operational strategies may assist airport operators first in investigating the compatibility of existing terminal processing facilities with the introduction of the NLA, and ultimately in preparing the future development plan.

Keywords: New Large Aircraft, NLA, Airport, Passenger Flow, Terminal, Passenger Terminal System, Passenger Volume

ENTIRE REPORT (Adobe Acrobat File – 1,620 KB)

Modeling the Pneumatic Subsystem of a S-cam Air Brake System

Shankar C. Subramanian, Swaroop Darbha and K. R. Rajagopal, Texas A&M University, July 2003, 56 pp. (167108-1)

The air brake system is one of the critical components in ensuring the safe operation of any commercial vehicle. This work is directed towards the development of a fault-free model of the pneumatic subsystem of the air brake system. This model can be used in brake control and diagnostic applications. Current enforcement inspections are done manually and hence are time consuming and subjective. The long-term objective is to develop a model-based, performance-based diagnostic system that will automate enforcement inspections and help in monitoring the condition of the air brake system. Such a diagnostic system can update the driver on the performance of the brake system during travel and with recent advancements in communication technology, this information can be remotely transferred to the brake inspection teams. The model of the pneumatic subsystem correlates the pressure transients in the brake chamber with the brake pedal actuation force and the brake valve plunger displacement. An experimental test bench was set up at Texas A&M University and the experimental data is used to corroborate the results obtained from the model.

Keywords: Modeling, Air Brake Systems, Commercial Vehicles

ENTIRE REPORT (Adobe Acrobat File – 698KBytes)

Restricting the Use of Reverse Thrust as an Emissions Reduction Strategy

Colin Rice and C. Michael Walton, University of Texas at Austin, July 2003, 118 pp. (167231-1)

As more metropolitan areas approach “non-attainment” status for ozone, air pollution at airports is becoming an increasingly important topic. Most proposed emissions reduction strategies target passenger automobiles and airport ground service equipment (GSE). At many airports, the future growth in oxides of nitrogen (NOx) emissions from aircraft is likely to offset any reduction achieved from GSE or passenger vehicles. In some metropolitan areas, airports may be responsible for as much as 10% of the regional NOx. As a result, other alternatives are needed for emissions reduction at airports.

Reverse thrust is commonly used along with wheel brakes to slow aircraft during landing and occasionally to “power-back” aircraft away from a boarding gate. Currently, air pollution emissions generated during reverse thrust are not included in airport emissions inventories. Since the majority of aircraft NOx emissions occur off-airport during climbout and approach, reverse thrust can be responsible for an additional 15% or more of the on-airport NOx. This can create significant air quality impacts in the vicinity of the busiest airports. This research will attempt to quantify and model the air quality effect of NOx emissions produced during reverse thrust, using Dallas/Ft. Worth International Airport as a case study.

Keywords: Emissions, Airport, Reverse Thrust, Air Pollution, Air Quality

ENTIRE REPORT (Adobe Acrobat File – 1,039 KB)

Intelligent Transportation Systems to Improve Elderly Persons’ Mobility and Decision Making within Departure Time Choice Framework

Anna R. Okola and C. Michael Walton, University of Texas at Austin, June 2003, 77 pp. (167531-1)

There is a general assumption that the elderly are unfamiliar or uncomfortable with technology – that has been the premise for most studies researching the benefits of Intelligent Transportation Systems (ITS) for elderly drivers. While the preconceived notions about technology and the elderly may ring true for older generations of the elderly, a marked change is to be expected for current and future elderly cohorts, as these groups are more likely to have grown up with the technology, or watched and participated in its development. In addition, currently available technologies such as in-vehicle systems are still considered luxury add-ons, and have been purchased by the elderly. Thus the question arises how ITS can enhance elderly persons’ mobility given that the society is generally aging, and that society is becoming more accustomed to new technologies. However, the challenge of predicting benefits for an aging cohort that is not yet elderly is two-fold, first the underlying assumption that behavior patterns will not change may have serious implications and secondly, the technologies themselves are still developing, and as such, the effects, in many cases, are yet to be observed. A dynamic assessment model is then needed to evaluate transportation systems for the society at large and the elderly in particular.

Keywords: Intelligent Transportation Systems, ITS, Mobility, Elderly, Advanced Traveler Information Systems, ATIS, Travel Behavior

ENTIRE REPORT (Adobe Acrobat File – 469 KB)

Developing an Intelligent Parking System for the University of Texas at Austin

Michelle Crowder and C. Michael Walton, University of Texas at Austin, May 2003, 71 pp. (167229-1)

Because there is an increasing interest from motorists to have access to real-time information while en-route to a particular destination, advances in Intelligent Transportation Systems (ITS) have focused on the dissemination of real time information. As central business districts, airports, transit stations, and shopping centers continue to become more crowded during peak times, demand for real-time parking information is increasing. University environments are no exception to this rule. With decreasing parking supply and increasing enrollments and faculty and staff numbers, universities are beginning to realize the importance of properly allocating available parking. Intelligent Parking Systems (IPS) can provide the positive guidance necessary to help university patrons find available parking quickly and safely; more specifically, patrons of the University of Texas at Austin, UT.

An Intelligent Parking System (IPS) could help the University of Texas reallocate parking and reduce congestion and illegal parks. Also, the university’s master plan is biased towards a system that provides university “wayfinding,” which can complement IPS. Variable Message Signs (VMS) have been considered by the university to provide “wayfinding” and parking information; however, VMS are expensive and will further clutter university street corners currently overridden with signage.

The best university IPS application should provide real-time parking information, reduce congestion, and reallocate parking for all university patrons creating more efficient use of university parking supply. Because IPS should be consistent with increased efficiency, patrons should not have to pay increased parking fees for the university’s implementation of IPS. The University of Texas should consider IPS implementation in conjunction with parking policy changes for successful deployment.

In order to meet the efficiency demands, the Intelligent Parking System needs to be utilized; if not utilized, IPS will have little or no affect on the university’s parking problems. The real challenge for the University of Texas is to begin to develop a parking system that meets the demands of the students, faculty, staff, and visitors that utilize university garage and surface parking. Current parking policy may hinder IPS effectiveness, however, if progressive changes are made to university parking policy, IPS could have positive effects on the supply and efficiency of parking at UT.

Keywords: Parking, Intelligent Transportation Systems, ITS, Intelligent Parking Systems, IPS, Advanced Parking Management Systems, Wayfinding

ENTIRE REPORT (Adobe Acrobat File – 353 KBytes)

Analysis of Effects of Alternative Fuels Legislation on State Highway Funds in the Southwest Region

Kathleen A. Hornaday, Mark A. Euritt and C. Michael Walton, University of Texas at Austin, May 2003, 126 pp. (712413-1)

Adoption of the Federal Clean Air Act, as well as numerous state clean air initiatives, has precipitated interest in alternative, “clean,” fuels. Implementation of alternative fuels has important implications for state highway programs which draw resources from motor fuel taxes. Conversion of gasoline and diesel engines to natural gas could potentially draw financial resources away from dedicated highway trust funds without decreasing utilization of the highway system. The principal objective of this research was to evaluate the impact of alternative fuels legislation on highway financing in the southwest region of the United States through the use of conversion scenarios based on new state laws.

Keywords: Alternative Fuels Legislation, Highway Financing, Highway User Taxes, Motor-Fuel Taxes, State Transportation Funds, Alternative Fuels, Clean Fuels, Federal Clean Air Act, Compressed Natural Gas (CNG), Conversion Process, Fuel Tax Exemptions, User-Pay Strategy, Annual Fixed Fee Method, BTU Tax, Federal CNG Fuel Tax

ENTIRE REPORT (Adobe Acrobat File – 308 KBytes)

A Unified Mixed Logit Framework for Modeling Revealed and Stated Preferences: Formulation and Application to Congestion Pricing Analysis in the San Francisco Bay Area

Chandra R. Bhat and Saul Castelar, University of Texas at Austin, April 2003, 50 pp. (167220-1)

This report formulates and applies a unified mixed-logit framework for joint analysis of revealed and stated preference data that accommodates a flexible competition pattern across alternatives, scale difference in the revealed and stated choice contexts, heterogeneity across individuals in the intrinsic preferences for alternatives, heterogeneity across individuals in the responsiveness to level-of-service factors, state dependence of the stated choices on the revealed choice, and heterogeneity across individuals in the state dependence effect. The estimation of the mixed logit formulation is achieved using simulation techniques that employ quasi-random Monte Carlo draws. The formulation is applied to examine the travel behavior responses of San Francisco Bay Bridge users to changes in travel conditions. The data for the study are drawn from surveys conducted as part of the 1996 San Francisco Bay Area Travel Study. The results of the mixed logit formulation are compared with those of more restrictive structures on the basis of parameter estimates, implied trade-offs among level-of-service attributes, heterogeneity and state dependence effects, data fit, and substantive implications of congestion pricing policy simulations.

Keywords: Revealed Preference, State Preference, Mixed Logit, Quasi-Monte Carlo Simulation, State Dependence, Unobserved Heterogeneity, Congestion Pricing

ENTIRE REPORT (Adobe Acrobat File – 192 KBytes)

Developing a Transportation Science Competition and Career Fair for Junior High and High School Students

Brooke R. Ullman and Debbie Jasek, Texas A&M University, April 2003, 70 pp. (167123-1)

With the dilemma of a challenged transportation workforce looming on the horizon, it is crucial that universities take a pro-active role in providing transportation professionals for the 21st century with the necessary tools to perform their roles within the industry. One way in which universities can provide these tools is through education and training. By exposing young students to transportation and the vast array of educational and career opportunities awaiting them, universities can increase the potential work force for the future. In turn, those young students who seek transportation as a career can work to maintain the complex transportation infrastructure in place and ensure mobility and prosperity for the future. A transportation science competition was hosted by the Texas Transportation Institute on the Texas A&M University campus. The competition provided outstanding junior high and high school students an opportunity to present research findings and ideas in a professional arena. Students who excelled in science and mathematics and enjoy academic competition were be targeted for participation.

Keywords: Transportation Careers, Transportation Fair, Science Competition, Educational Outreach

ENTIRE REPORT (Adobe Acrobat File – 892 KB)

An Evaluation of Third-Party Coordination Among Service Providers in the Greater Houston and Harris County Area

Edward Owens and Carol A. Lewis, Texas Southern University, March 2003, 27 pp. (466010-1)

As the Houston-Galveston urban area strives to attain air quality standards mandated by the Clean Air Act Amendment, acquisition of federal funds remains competitive, and the cost of doing business continues to rise, it will become increasingly more important for third-party service providers to coordinate their services. The purpose of this study is to document the efforts of numerous organizations’ activities to improve coordination among third-party service providers in the Greater Houston and Harris County area. The study will provide background information and a literature review of third-party coordination across the country. The study will examine the feasibility and development of a demonstration project aimed at coordinating the service operations of selected third-party providers in the Greater Houston area. Additionally, the study will highlight the findings from a research project conducted by Multisystems aimed at developing a Transportation Coordination Model for Harris County. Next, the study will provide perspectives from the Harris County Transportation Coordinating Council, including the American Red Cross, Houston Galveston Area Council (HGAC) and the Office of Community Transportation Services regarding third-party coordination in Harris County. Finally, the study will provide a summary of current efforts and suggestions on ways to further enhance third-party coordination in Houston and Harris County.

It is hoped that this report will serve as a valuable guide to transportation providers, transportation planners, policy officials, social service agencies and other interested parties.

Keywords: Coordination, Transportation, Third-Party

ENTIRE REPORT (Adobe Acrobat File – 108 KBytes)

Opening the Border to Cross-National TruckTraffic: The Texas Perspective

Jerry L. Jamieson Jr., and Robert Harrison, University of Texas at Austin, December 2002, 53 pp. (473700-00067-1)

Few Issues have been as contentious as the opening of the Texas-Mexico border to cross-national truck traffic.  This study examines issues surrounding an open border and assesses the possible benefits and costs for the citizens of Texas.  The study uses economic data on trade volumes and employment to assess the impacts that an open border will have on Texas.  By removing border trucking restrictions, trade and its associated positive economic benefits should increase for Texas and consumer prices should fall.

An open border should lead to reduced congestion, reduced accidents, and less pollution (air and noise) for Texas border communities.  To assess the most contentious open border issue, safety, studies used to evaluate Mexican truck safety are scrutinized, the politics of the safety issue are examined, and recommendations are made for properly evaluating Mexican truck safety.  After assessing the economic, environmental, social, and safety issues, this study comes to the conclusion that, although an open border produces winners and losers, it will be a net benefit to the state.  However, transportation-dependent border economies will suffer I the short-term once open border trucking operations take effect.

Keywords: Border, Texas-Mexico Border, Trade Volumes, Truck Safety, Mexican Trucks

ENTIRE REPORT (Adobe Acrobat File – 264 KB)

Transit-Operated Vanpools in the United States: Selected Case Studies

Laura L. Higgins and Robin I. Rabinowitz, Texas A&M University, December 2002, 40 pp. (167122-1)

Vanpools are one way of expanding public transit service into new markets and lower-density corridors. This research documents case studies of transit-operated vanpools in the United States, including information on ridership numbers, funding sources, primary markets served, and lessons learned.

Keywords: Vanpool, Transit, Alternate Commute

ENTIRE REPORT (Adobe Acrobat File – 123 KB)

Investigation of an ITS Framework for Congestion Pricing

Colleen M. McGovern and C. Michael Walton, University of Texas at Austin, October 2002, 85 pp. (167529-1)

This report documents an investigation of an ITS framework for congestion pricing. It begins with a review of the literature related to congestion pricing and ITS benefits prediction methods, which were used as a foundation for the development and analysis of an ITS framework for congestion pricing. In order to develop the framework, activities associated with congestion pricing were first described and then ITS elements were identified to perform these tasks. Analysis of the associated benefits of using the ITS framework for congestion pricing was attempted using two different computer based ITS analysis tools: SCReening for ITS (SCRITS) and ITS Deployment Analysis System (IDAS). Finally the results and findings of this study are presented.

Keywords: ITS, ITS Framework, ITS Benefits, ITS Applications, Congestion, Pricing, Congestion-Pricing, IDAS, SCRITS

ENTIRE REPORT (Adobe Acrobat File – 626 KB)

The Education of Transportation Planning Professionals

Susan Handy, Lisa Weston, Jumin Song, K. Maria D. Lane, Jennifer Terry, University of Texas at Austin, October 2002, 139 pp. (167222-1)

The practice of transportation planning at the regional level has evolved substantially over the past several decades. Once defined as largely a technical exercise, in which the calculation of required roadway capacity was the pre-eminent activity, transportation planning now encompasses a wide range of sometimes conflicting problems and demands, from growing levels of congestion and worsening air quality to neighborhood preservation and social equity concerns. But are the curricula in the planning and engineering programs that educate and train transportation professionals adequately preparing them for these new challenges? The objective of the study summarized in this paper was to compare the kinds of knowledge and skills important to transportation professionals today to the kinds of knowledge and skills that planning and engineering programs provide their students in order to highlight areas for improvement and suggest ways to enhance the education of transportation professionals. The research involved several components: a literature review on transportation education and planning education, an analysis of ISTEA and TEA-21 planning requirements, construction and analysis of a database on planning programs and selected transportation engineering programs as to their course offerings in the area of transportation planning, a survey of transportation planning professionals, and interviews with selected transportation planning educators and professionals. This report presents the findings from those efforts and suggests several important issues for transportation educators to address to improve the quality of education for transportation planning professionals.

Keywords: Transportation Planning, Transportation Education, Transportation Profession

ENTIRE REPORT (Adobe Acrobat File – 595 KB)

 

Implementation of a Database and Information System for Forensic Investigation of Pavements

Zhanmin Zhang and Chunrong Zhou, University of Texas at Austin, September 2002, 106 pp. (167203-1)

This report describes the implementation of a database and information system for forensic investigation of pavements by enhancing the 1998 version of the ForenSys database software. The enhanced ForenSys database software can serve as the center component of an integrated forensic information and analysis system for analyzing forensic related data and information and producing forensic reports. In the study, a literature review on the basic concept and current practice of forensic engineering has been performed; the system design concept of the relational database has been applied; the 1998 version of the ForenSys database software has been improved; the guidelines of using the ForenSys software have been developed; and a computerized procedure for automatically importing PMIS data and Layer data to the ForenSys database has been developed.

Keywords: Forensic Investigation, Database, Information Systems, Pavement Management Systems

ENTIRE REPORT (Adobe Acrobat File – 1 MB)

 

The Impacts of U.S.-Latin American Trade on the Southwest’s Economy and Transportation System: Case Studies of Coffee and Steel on the U.S.-Brazil Trade Corridor

Leigh B. Boske and John C. Cuttino, University of Texas at Austin, September 2002, 146 pp. (167221-1)

This report traces economic and transport impacts of U.S.-Latin America trade through case studies of coffee and steel from Brazil to the U.S.-destination Port of Houston. It is the second of a two-report series on economic impacts, following The Impacts of U.S.-Latin American Trade on the Southwest’s Economy and Transportation System: An Assessment of Impact Methodologies, and adopting a similar case study methodology to more adequately measure the cumulative impacts of trade along a commodity’s value/supply chain.

The recommended methodology entails the adoption of the transportation corridor and the commodity shipments as units for analysis, and the case studies of coffee and steel delineate how trade and transportation actually take place. The report follows trade and transport through various stages of production and consumption from the originating region in Brazil, through the Brazilian gateway ports of Vitória and Santos, to arrival at the Port of Houston with analysis of the commodities movements along multiplicative supply chains. Cumulative impacts are measured in relation to actual movement and activity. In this way, the report identifies more policy-relevant impacts, identifies trade opportunities, and reveals factors aiding and impeding the effective functioning of a trade/transport corridor.

Keywords: Trade Corridor, Transportation Corridor, Logistics, U.S.-Brazil Trade, U.S.-Latin America Trade

ENTIRE REPORT (Adobe Acrobat File – 2,684 KBytes)

Uncertainty in Integrated Land Use-Transport Models: Simulation & Propagation

Sriram Krishnamurthy and Kara Kockelman, University of Texas at Austin, September 2002, 29 pp. (167523-1)

This work examines the propagation of uncertainty in outputs of a standard integrated model of transportation and land use. Austin-calibrated DRAM-EMPAL predictions of residence and work locations are used as inputs to a four-step travel demand model (TDM), and the resulting travel times are fed forward into the future period’s land use models. Covariance in inputs (including model parameters and demographic variables) was accommodated through multivariate Monte Carlo sampling of 200 scenarios. Variances in land use and travel predictions were then analyzed, over time, and as a function of input values. Results indicate that output variations were most sensitive to the exponent of the link performance function, the split of trips between peak and off-peak and several trip generation & attraction rates. 20 years in the future, final uncertainty levels (as measured by coefficients of variation) due solely to input and parameter estimation errors are on the order of 38% for total regional peak-period VMT, 45% for peak-period flows, and 50% and 37% for residential and employment densities, respectively.

Keywords: Uncertainty Outputs, Travel Demand Model, Land-Use, Covariance

ENTIRE REPORT (Adobe Acrobat File – 195 KB)

Uncertainty in Integrated Land Use-Transport Models

Anant Pradhan and Kara Kockelman, University of Texas at Austin, September 2002, 34 pp. (167223-1)

This study examines the impact of uncertainty in the land use component of a partially integrated land use-transportation modeling system called UrbanSim. Outputs from the land use model (LUM) act as inputs for a traditional 4-step travel demand model (TDM), and travel times from the traffic-assignment stage of the TDM are fed forward into the subsequent years LUM. This work examines the propagation of uncertainty across model stages as well as at each model stage over time. A factorized design approach is used to model uncertainty in demographic inputs (which include aggregate growth rates and mobility rates) to the land use model, as well as uncertainty in various model parameters. The results suggest that while several model inputs may affect model outputs in the short run, only those inputs that have a cumulative effect are likely to have a significant impact on outputs in the long run. The results also suggest that uncertainty in model outputs may increase for the first few years for which the model is run, as modified inputs send shocks through the urban system. However, the level of uncertainty appears to come down in later years, as households, jobs, and developers respond to changed input conditions.

Keywords: Uncertainty, Integrated Land-Use, Modeling, Forecast, Urban Systems

ENTIRE REPORT (Adobe Acrobat File – 139 KB)

 

ISTEA and Intermodalism: A User and Reference Guide to Intermodalism

Edward Owens and Carol A. Lewis, Texas Southern University, September 2002, 60 pp. (466050-1)

The Intermodal Surface Transportation Efficiency Act (ISTEA) was passed in 1991 with the objective of encouraging greater coordination and efficiency of transportation movement among modes. The Act issued a challenge to transportation professionals to shift the old paradigms and explore new opportunities to improve the integration of modes, as well as to ask new questions about coordinated freight and passenger movements.

As public and private transportation providers deliberate the strengths and weaknesses of the first Act, it is important to record what has evolved in the area of intermodalism at the end of the six-year authorization period. This report examines some of the past challenges and requirements of ISTEA legislation. It reviews the meaning of intermodalism across modes for freight and passenger service. The report takes an in-depth look at public/private intermodal alliances that are working efficiently. These examples of intermodalism across the country are scanned, focusing on the state-of-the-industry. Documents are examined and synthesized to highlight these efforts. Elements identified as barriers to intermodalism are also identified. Recommendations to improve intermodalism are considered. Next, we examine the role of MPOs in intermodal transportation planning and look at the benefits of a National Intermodal Transportation System. Lastly, the report looks at ISTEA’s successor, The Transportation Equity Act for the 21st Century (TEA 21).

It is hoped that this publication will be a valuable guide for Federal, state and local planners, policymakers, and transportation practitioners.

Keywords: Intermodalism, ISTEA, Freight

ENTIRE REPORT (Adobe Acrobat File – 211 KB)

Compendium: Papers on Advanced Surface Transportation Systems, 2002

Texas A&M University, August 2002, 362 pp. (473700-00003-4)

This document is the culmination of the twelfth offering of a Mentors Program at Texas A&M University on Advanced Surface Transportation Systems which was presented in 2002 by the Advanced Institute in Transportation Systems Operations and Management. The Program allows participants to work closely with recognized experts in the field of intelligent transportation systems (ITS) and traffic operations and management. The highly successful Mentors Program has been available to transportation engineering graduate students at Texas A&M University since 1991. In 2002, the Program was available to state Department of Transportation employees as well.

As part of the Mentors Program six top-level transportation professionals from private enterprise and departments of transportation were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems in early June. Immediately following the Symposium, the participants enrolled in the Program took part in a Forum and a Workshop with the invited mentors and the course instructor. Each participant held numerous discussions with the mentors and course instructor to identify a topic area for a paper. The state DOT participants selected topics that had direct application to the needs of their respective states. Each participant worked with his/her mentor and course instructor to finalize a topic area and objectives for a paper. In addition to discussions with the course instructor, the participants (communicating via telephone, e-mail, fax and mail) worked directly with the mentors throughout the summer while preparing their papers. The mentors and the state DOT employee participants returned to the Texas A&M University campus in late July for formal presentations of the papers.

Keywords: Intelligent Transportation Systems, Advanced Traffic Management Systems, Traffic Management Centers, Dynamic Message Signs, Incident Management, Commercial Vehicle Incidents, Ramp Metering, Freeway Work Zones, Highway Construction, Highway Advisory Radio, Red Light Cameras, Incidents During Severe Weather, Travel Time, Roundabouts

REPORT PREFACE AND TABLE OF CONTENTS (Adobe Acrobat File – 10.7 MB)

Compendium of Student Papers: 2002 Undergraduate Transportation Engineering Fellows Program

Shawn Turner, editor, Texas A&M University, August 2002, 180 pp. (473700-00003-5)

This report is a compilation of research papers written by students participating in the 2002 Undergraduate Transportation Engineering Fellows Program. The ten-week summer program, now in its twelfth year, provides undergraduate students in Civil Engineering the opportunity to learn about transportation engineering through participation in sponsored transportation research projects. The program design allows students to interact directly with a Texas A&M University faculty member or TTI researcher in developing a research proposal, conducting valid research, and documenting the research results through oral presentations and research papers.

The papers in this compendium report on the following topics, respectively: 1) color recognition of retroreflective raised pavement markers; 2) impacts of localized congestion on mobile source emissions; 3) transportation improvement strategies for Houston’s Texas Medical Center; 4) effects of access management on vehicle crashes; 5) computer micro-simulation analysis of intersections near highway-railroad grade crossings; and 6) the costs and benefits associated with electronic toll collection and variable toll rates.

Keywords: Retroreflective Raised Pavement Markers, Mobile Source Emissions, Transportation Improvement Strategies, Access Management, Computer Micro-Simulation, Highway-Railroad Grade Crossings, Electronic Toll Collection, Variable Toll Rates

ENTIRE REPORT (Adobe Acrobat File – 11.6 MB)

Effects of In-Vehicle Distractor Complexity on Driving and Emergency Response Performance

Michael Manser and Dana M. Even, Texas A&M University, June 2002, 149 pp. (167126-1)

Imagine yourself driving along a dark foggy road, you are lost, are becoming worried, and refuse to pull over for any period of time in an unfamiliar area. To belay fears you switch on the in-vehicle map. This should help you to determine where you are and how to return to familiar territory. When you are scrolling through menu options your cell phone rings and you answer. At the same time your child in the back seat starts to cry and a buzzer in the vehicle is warning of a potential engine failure. All of a sudden, in the fog you see a vehicle approaching you…in your lane! While this example is exaggerated, it is a situation where a driver is presented with a variety of distracters that singularly or in concert may detract from the driving task and detract from a driver’s ability to react to an emergency event. Previous research has shown that singular distracters, such as cell phones, can significantly detract from the driver’s ability to perform the driving task. However, despite the marked influence on the driving task, little research has evaluated the relative influence of differing levels of distracter complexity influence driver behavior. The purpose of the two experiments presented here was to perform preliminary tests to determine if varying levels of distracter complexity differentially influence driver behavior. A second purpose was to determine the influence of varying levels of distracter complexity on drivers’ ability to react to an emergency event. Results of the studies indicate that driver performance was degraded with the introduction of a distracter and when the distracter is presented through a visual information delivery mode driver performance was degraded differentially with differing levels of distracter complexity. Results also indicate that when drivers are presented with an emergency response scenario their primary reaction is to brake. However, the number of participants who braked increased with the inclusion of a distracter and was differentially influenced by the level of complexity of the distracter. These results lend support to the contention that driver performance is negatively influenced by the inclusion of and increasing levels of complexity of a distraction and that this may be due to increasing amount of attentional resources that are captured with the introduction of a distracter.

Keywords: Driving, Distraction, Distractors, Emergency Response, Emergency Maneuver

ENTIRE REPORT (Adobe Acrobat File – 619 KB)

 

Sustainable Transportation: Conceptualization and Performance Measures

Josias Zietsman and Lurence R. Rilett, Texas A&M University, March 2002, 163 pp. (167403-1)

Sustainable transportation attempts to address economic development, environmental stewardship, and social equity of current and future generations. While numerous qualitative studies have been performed on this topic, there has been little quantitative research and/or implementation of sustainable transportation concepts. The main reasons for this are related to a lack of understanding of sustainable transportation and a lack of quantified performance measures. To address this problem, a comprehensive definition for sustainable transportation was developed, as well as a framework on how to identify, quantify, and use performance measures for sustainable transportation in the transportation planning process. The proposed framework was applied to a test bed, comprising two freeway corridors in Houston, Texas.

New innovations such as Automatic Vehicle Identification (AVI) data and the Transportation Analysis and Simulation System (TRANSIMS) model make it possible to obtain travel-related information at highly disaggregate levels. This information can be used to quantify sustainable transportation performance measures at the individual level and levels of spatial and temporal disaggregation, which has previously not been possible. The AVI data, the TRANSIMS model, and a number of transportation environmental impact models were used to quantify the performance measures at various levels of aggregation.

The performance measures that were quantified on disaggregate levels were compared to measures that were quantified with traditional aggregate data sets. It was found that the traditional approach is much less accurate due to a loss of detail and the effect of aggregation bias. It was illustrated that the performance measures based on disaggregate data can potentially provide different results as compared to aggregate approaches, when used with multi-objective decision-making techniques in transportation planning. Finally, it was demonstrated that the disaggregate approach can be used to allocate responsibility for negative externalities, and to assess the sustainability as experienced by different user groups.

Keywords: Sustainable Transportation, Performance Measures, Disaggregate, Decision-Making, TRANSIMS, AVI Data

ENTIRE REPORT (Adobe Acrobat File – 1.1 MB)

Developing an Integrated Management System for the Urban Transportation Infrastructure

Zhanmin Zhang, Fuat Aki, and W. Ronald Hudson, University of Texas at Austin, February 2002, 151 pp. (167511-1)

This report describes the development of an integrated management system for urban transportation infrastructure. The developed system integrates pavements and bridges at both network and project level management.

A computer program was developed as a result of this study. The developed computer program is user-friendly and takes full advantage of Graphical User Interface (GUI) technology. In addition, a combined priority index was developed to compare pavements and bridges on the same scale. In developing this index, the variables that are common to both pavements and bridges were used including: 1) Traffic, 2) Condition, 3) Width, and 4) Age.

Keywords: Urban Transportation Infrastructure, Infrastructure Management System, Pavement and Bridge Management, Integrated Management System, Urban Roadway Management, Brigit, TBSS

ENTIRE REPORT (Adobe Acrobat File – 700 KB)

 

GIS to Identify Strategic Freight Corridors in Texas

Brian W. Craig and C. Michael Walton, University of Texas at Austin, February 2002, 140 pp. (467504-1)

The goals of this report are to identify the strategic freight corridors (SFC) in the state of Texas. Freight corridors can be defined for various modes of transportation. For this project, however, only the truck mode was evaluated. A model was created to identify areas of economic significance within the state. For the purpose of data collection, the county was used as the analysis region.

The model developed identified the economically significant counties in the state using economic and non-economic data to capture the demand to move goods within a county. The economic data consisted of the county income date for the five largest industries in the state that required a significant demand to transport goods. The non-economic income data consisted of dummy variables that modeled the presence of intermodal and border crossing facilities. A final score for each county was computed by assigning the weighting factor to the scores for each criterion and summing up each criterion score. A cutoff value was calculated to determine the economic significance of a county.

Forty-six counties were determined to be economically significant. The SFC network was selected by identifying the economically significant counties and then interconnecting these counties with a minimal network that was not too circuitous.

A sensitivity test was performed to determine how the model’s weighting scheme affected the selection of highways for the SFC network. This sensitivity test revealed that the weighting scheme had no effect on the selection of highways for the SFC network.

Keywords: ITS, GIS, Freight Corridors

ENTIRE REPORT (Adobe Acrobat File – 2.4 MB)

Development and Implementation of a Telecommuting Evaluation Framework, and Modeling the Executive Telecommuting Adoption Process

Vaishali Punamchand Vora and Hani S. Mahmassani, University of Texas at Austin, February 2002, 128 pp. (167505-1)

This work proposes and implements a comprehensive evaluation framework to document the telecommuter, organizational, and societal impacts of telecommuting through telecommuting programs. Evaluation processes and materials within the outlined framework are also proposed and implemented. As the first component of the evaluation process, the executive survey is administered within a public sector agency. The survey data is examined through exploratory analysis and is compared to a previous survey of private sector executives. The ordinal probit, dynamic probit, and dynamic generalized ordinal probit (DGOP) models of telecommuting adoption are calibrated to identify factors which significantly influence executive adoption preferences and to test the robustness of such factors. The public sector DGOP model of executive willingness to support telecommuting under different program scenarios is compared with an equivalent private sector DGOP model. Through the telecommuting program, a case study of telecommuting travel impacts is performed to further substantiate research.

Keywords: Telecommuting, Ordinal Probit, Dynamic Probit Model, Economic, Individual and Aggregate Implications of Telecommuting

ENTIRE REPORT (Adobe Acrobat File – 435KBytes)

Understanding the Growth in Non-Work VMT

Susan Handy, Andrew DeGarmo, and Kelly Clifton, University of Texas at Austin, February 2002, 72 pp. (167802-1)

If the anecdotal evidence is to be believed, Americans are driving more than ever – and not just for commute trips. Americans don’t seem entirely happy about this trend, at least some of this increase in driving appears to be a matter of choice rather than necessity. Either way, the trend has important social, economic, and environmental implications. An understanding of the forces behind this trend might lead to policy responses that reduce how much households drive – or at least how much they have to drive. This report presents a preliminary effort to understand the apparent increase in non-work vehicle-miles-traveled (VMT) at the household level. The first step was to review available data on travel trends to confirm that non-work VMT is in fact increasing. While available data sources provide convincing evidence of this trend, they are far from conclusive. The second step was to explore factors associated with households themselves – the demand side – and with the choices available to households – the supply side. This exploration included an assessment of the trend in each factor and the development of hypotheses about its effect on non-work travel. The final step in this preliminary study was to summarize the findings from existing models of non-work travel behavior on what variables significantly impact non-work travel and in what direction. The report concludes with a discussion of what questions remain and what research approaches may prove fruitful in answering them.

Keywords: Non-Work Travel, Shopping Travel, Travel Behavior, Travel Trends

ENTIRE REPORT (Adobe Acrobat File – 231 KBytes)

Impact of Electronic Commerce on Logistics Operations: A Focus on Vendor Managed Inventory (VMI) Strategies

Mouhamad Y. Rabah and Hani S. Mahmassani, University of Texas at Austin, February 2002, 78 pp. (167227-1)

This report investigates the impacts of Information and Communication Technologies (ICT) and the Internet on logistics operations. The major contributions are: 1) an overview of the Internet growth during the past five years, as it relates to electronic commerce 2) a conceptual framework that assesses the impact of ICT on supply chain operations, 3) two modeling schemes representing no information sharing (NIS) and information sharing (IS) scenarios among multiple retailers and one supplier, and 4) cost reductions achievable through information sharing in a two-echelon supply chain where the supplier adopts a Vendor Managed Inventory (VMI) policy.

Reported statistics concerning Internet growth show large discrepancies, reflecting different traffic measurement methodologies adopted by various companies and agencies. Advantages and disadvantages of currently used techniques are presented. Trends in the development of electronic business-to-customer (B2C) and business-to-business (B2B) commerce sectors are discussed, and various forecasts are compared to actual observations where applicable.

A major industry affected by ICT is the logistics industry. A framework reflecting the transformation of logistics operations into supply chain management with real-time information and collaboration is presented. The framework reflects the shift in logistics operations towards strategies that allow faster reaction to customer demand changes facilitated by technological advancements and collaboration among various parties. These policies include Merge-In-Transit (MIT), Time Definite Delivery (TDD), postponement strategy, and VMI. Advantages and disadvantages of logistics relational settings and operations are discussed.

Finally, cost reductions achievable through information sharing among multiple retailers and one supplier are quantified. Simulation experiments are developed to model a setting with no information sharing (NIS) based on the Economic Order Quantity (EOQ), which is contrasted to a scenario with information sharing (IS) based on a VMI policy. Heuristic algorithms are applied to solve both problems. Results, based on randomly generated instances, show that the main benefit to retailers is a major decrease in stock-out costs. The major benefit for the supplier is the reduction in the so-called bullwhip effect, which translates into a decrease in inventory holding cost. Finally, although the number of visits from the supplier to retailers increased significantly, the transportation cost decreased in almost all cases reflecting the use of more efficient routes by the supplier when bundling retailers’ demands.

Keywords: Logistic Operations, Vendor Managed Inventory, Electronic Commerce, Communication Technology

ENTIRE REPORT (Adobe Acrobat File – 428KBytes)

Dynamic Decision and Adjustment Processes in Commuter Behavior Under Real-Time Information

Karthik K. Srinivasan and Hani S. Mahmassani, University of Texas at Austin, February 2002, 252 pp. (167204-1)

Advanced Traveler Information Systems (ATIS), by providing real-time traffic information, can assist trip-makers in selecting efficient travel choices, and aid the attainment of desirable system goals including reduced costs and increased efficiencies. The success of ATIS in achieving such goals critically depends on user behavior in response to information. This research focuses on investigating dynamic aspects in commuter behavior under real-time information. A dynamic interactive travel-behavior simulator, that enables a consistent representation of the nonlinear time-dependent interactions between network performance, trip-makers choices, and information, is used to observe trip-maker behavior. Using the simulator, interactive experiments are conducted where a range of experimental factors including network loading, day-to-day traffic evolution and ATIS information strategies are varied and the consequent trip-maker behavior is observed. Constituent models are proposed to analyze the choice dimensions of route, departure time, and compliance. The dynamic kernel logit (DKL) formulation is presented for analyzing these data and its theoretical and computational suitability established. The results confirm the significance of compliance and inertia as key mechanisms influencing route choice. Departure time adjustments appear to be based on a sequential heuristic search. Calibrated models also provide evidence of learning, adjustment, perception, judgment, and updating processes in trip-maker behavior. Empirical results indicate that real-time information and time-dependent network conditions are strong determinants of trip-maker behavior in a commuting context. The nature and quality of ATIS information (accuracy and reliability), the magnitude of network loading and its day-to-day evolution, and users’ past traffic experience are important influences on how commuters select routes and departure times. At the unobserved level, general dynamic and stochastic patterns, including, heterogeneity, state-dependence, habit-persistence, and correlations are present in trip-makers’ decisions. These substantive results have important implications for network state prediction, travel demand forecasting, design and evaluation of ATIS services and deployment of Intelligent Transportation System (ITS) programs. User behavior models developed here can be integrated with dynamic network traffic assignment models to obtain more accurate system performance modeling capabilities with considerable applications in tactical and strategic system planning and traffic operations.

Keywords: Commuter Behavior, Real-Time Information, ATIS, ITS, ATMIS

ENTIRE REPORT (Adobe Acrobat File – 1.4 MB)

Arterial Street High-Occupancy Vehicle (HOV) Lanes in Texas

Katherine F. Turnbull, Texas A&M University, January 2002, 53 pp. (60042-1)

This report examines the current use of high-occupancy vehicle (HOV) lanes on arterial streets in cities in Texas and throughout North America. It documents the application of downtown bus malls and bus-only lanes, as well as arterial street bus and HOV lanes in major travel corridors and suburban areas. Examples of providing priority for buses at signalized intersections are also highlighted. Information is presented on the design and the use of different treatments. General guidelines for planning and designing arterial street HOV lanes are presented. Potential benefits from arterial street HOV facilities include increasing vehicle occupancy levels, improving fuel efficiency, reducing energy use, and enhancing air quality levels.

Keywords: High-Occupancy Vehicle Lanes, HOV Facilities, Arterial Street HOV Lanes, Bus Lanes, Carpool Lanes, Transit Enhancements, Bus-Only Facilities

ENTIRE REPORT (Adobe Acrobat File – 3 MB)

A Conceptual Examination of the Impact of Traffic Control Strategies on Vehicle Emission and Fuel Consumption

Lenin Williams and Lei Yu, Texas Southern University, September 2001, 72 pp. (467203-1)

The federal government has charged the Environmental Protection Agency (EPA) with the responsibility of controlling and/or reducing the adverse levels of vehicle emissions, which result in unacceptable amounts of environmental pollution nationwide. In order to achieve this goal, the EPA, in turn, has mandated the installation of control technology in newer vehicles and more environmentally friendly new fuels. Theoretically, though, additional success could be achieved through the use of more emission sensitive traffic control strategies. The feasibility of this assumption can be tested by studying the real impacts of today’s advanced technology applications in transportation management on environmental factors. These impacts, in fact, are the basis for the design and implementation of a new generation of traffic management strategies.

However, the fact is that traditional traffic control strategies and/or traffic modeling programs, designed to comply with EPA requirements, have focused on travel time as their basis for reduction objectives. It should be understood, however, that these travel time minimization strategies, in general, do not simultaneously minimize fuel emissions or fuel consumption and hence, may not meet the environmental goals sought by EPA.

Specifically, different traffic management operational strategies can have different effects on a vehicle’s speed profile, which includes acceleration, deceleration, cruise and idle events. Further, it is these speed changes that affect the levels of the vehicle’s tailpipe emissions, which are made up of the potentially harmful pollutants of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), and fuel consumption. These emissions therefore, are sensitive to the traffic control strategies, such as signal timing settings, ramp metering, incident management, HOV lanes and toll collection utilized in real networks.

The objective of this research is to investigate some of the specific relationships between traffic signal settings and the resultant effects on vehicle fuel consumption, emissions levels and travel times as a means of identifying a basis for deriving optimal, environmentally sensitive traffic control strategies.

Keywords: Traffic Simulation, Traffic Modeling, ITS, Network Evaluation

ENTIRE REPORT (Adobe Acrobat File – 247KBytes)

Limits on Access in Low-Income Neighborhoods and the Travel Patterns of Low-Income Households

Kelly Clifton and Susan Handy, University of Texas at Austin, September 2001, 55 pp. (167502-1)

In many poor urban areas, retail and service establishments are not abundant and those retail centers that do exist often offer lower quality products at higher prices. To compound the problem, poor households lack the personal resources that might compensate for inadequate local access. They often don’t have the option of traveling to stores or other destinations beyond their neighborhood, and they can’t move to neighborhoods with better local access. Despite the constraints of inferior access and limited resources, the poor must nevertheless find ways to take care of their household needs as best they can, whether that means making do with the goods and services available within the neighborhood, finding ways to get to destinations outside of the neighborhood, or simply doing without. The travel patterns exhibited by low-income households should thus reflect, although often indirectly, the limited options they have and the ways in which they are able to go about their household provisioning. This study takes a look at levels of accessibility to basic services in low-income neighborhoods and explores the implications of limited accessibility and household constraints on non-work travel for low-income households for the case of Austin, TX. Key findings include lower auto ownership, lower trip frequencies, higher use of transit and walking, shorter trip distances but longer trip times, and less person-miles-traveled for low-income households. The results raise interesting questions about how low-income households make the most of their limited choices.

Keywords: Travel Patterns, Low Income Neighborhoods, Low-Income Households, Limited Access

ENTIRE REPORT (Adobe Acrobat File – 326KBytes)

Modeling Attraction-End Choice for Urban Recreational Trips: Implications for Transportation, Air Quality and Land-Use Planning

Michael A. Pozsgay and Chandra R. Bhat, University of Texas at Austin, August 2001, 63 pp. (167800-1)

Attraction-end choice studies have primarily focused on non-urban recreational trips or non-recreational urban trips. Relatively little attention has been focused in the literature on urban recreational trips. In contrast, urban recreational trips are contributing increasingly to overall urban travel. In this paper, we examine attraction-end choice models for home-based urban recreational trips. A non-linear-in-parameters multinomial logit model is estimated using the 1996 Dallas-Fort Worth household activity survey. The effects of level-of-service, zonal attributes, trip attributes, and socio-demographic variables on recreational attraction-end choice are examined, and the implications of the results for land-use, transportation planning, and air quality analysis are discussed.

Keywords: Transportation Planning, Transportation Air-Quality, Land-Use Planning, Demographic Modeling

ENTIRE REPORT (Adobe Acrobat File – 202KBytes)

Life Cycle Cost Analysis of Portland Cement Concrete Pavements

William James Wilde, Steve Waalkes and Rob Harrison, University of Texas at Austin, August 2001, 195 pp. (167205-1)

This report describes the development of a new life cycle cost analysis methodology for portland cement concrete pavements which considers all aspects of pavement design, construction, maintenance and user impacts throughout the analysis period. It predicts pavement performance using state of the art performance models and reliability concepts, from which it determines maintenance and rehabilitation needs.

Any construction performed on the roadway has associated construction and user costs. Also associated with all highway pavement construction are external costs, upon which it is difficult if not impossible to place a value. This methodology models the effects of construction on all these aspects and, where the effects cannot yet be quantified, allows new models to be added.

Reliability concepts are used with individual models when possible, and the overall variability of the total life cycle cost is estimated. Using reliability concepts and the variability in all aspects of construction and cost models, the design engineer can define a level of confidence for predicting total life cycle costs, user costs, accidents and other output parameters considered in the methodology.

The modular nature of the methodology allows it to be updated with new or better performing models for predicting pavement performance, user costs, and external costs associated with highway pavement construction. New pavement types such as asphalt concrete and pre-stressed concrete can also be added to the analysis in the future, using proper performance models and maintenance and rehabilitation strategies.

Many existing life cycle cost methodologies utilize preprogrammed maintenance and rehabilitation actions to determine the total life cycle cost of a particular alternative. This new methodology, however, determines when maintenance and rehabilitation activities will be required by predicting the distresses and the condition of the pavement due to traffic and environmental loading.

Keywords: Pavement Life Cycle Cost, Pavement Performance, Portland Cement Concrete Pavement, Highway Pavement Construction

ENTIRE REPORT (Adobe Acrobat File – 1.7 MB)

Compendium: Papers on Advanced Surface Transportation Systems, 2001

Texas A&M University, August 2001, 364 pp. (473700-00003-3)

This document is the culmination of the eleventh offering of a Mentors Program at Texas A&M University on Advanced Surface Transportation Systems which was presented in 2001 by the Advanced Institute in Transportation Systems Operations and Management. The Program allows participants to work closely with recognized experts in the field of intelligent transportation systems (ITS) and traffic operations and management. The highly successful Mentors Program has been available to transportation engineering graduate students at Texas A&M University since 1991. In 2001, the Program was available to state Department of Transportation employees as well.

As part of the Mentors Program six top-level transportation professionals from private enterprise and departments of transportation were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems in early June. Immediately following the Symposium, the participants enrolled in the Program took part in a Forum and a Workshop with the invited mentors and the course instructor. Each participant held numerous discussions with the mentors and course instructor to identify a topic area for a paper. The state DOT participants selected topics that had direct application to the needs of their respective states. Each participant worked with his/her mentor and course instructor to finalize a topic area and objectives for a paper. In addition to discussions with the course instructor, the participants (communicating via telephone, e-mail, fax and mail) worked directly with the mentors throughout the summer while preparing their papers. The mentors and the state DOT employee participants returned to the Texas A&M University campus in late July for formal presentations of the papers.

Keywords: Intelligent Transportation Systems, Advanced Traffic Management Systems, Portable Traffic Management Systems, Advanced Traveler Information Systems, Incident Management, Intelligent Speed Adaptation, Freeway Work Zones, Advanced Warning Devices, Portable Television Camera System, Bus Priority Systems, Travel Time Estimation

REPORT PREFACE AND TABLE OF CONTENTS (Adobe Acrobat File – 11.8 MB)

An Investigation of Integrated Transit Service

Mark Hickman and Kelly Blume, Texas Transportation Institute, August 2001, 68 pp. (472840-00023-1)

In the United States, many transit agencies are considering integrating their demand-responsive service with traditional fixed-route service. In some cases, it may be advantageous to the transit agency or to the passenger to coordinate traditional demand-responsive transit service with fixed-route service. The demand-responsive service connects passengers from their origin to the fixed route service and (or) from the fixed route service to their final destination. Such a service is expected to reduce the cost of transit service, but also will affect the level of service experienced by passengers. The integrated transit service problem is to schedule both passenger trips (or itineraries) and vehicle trips for this service. In considering the literature, this research proposes a scheduling method that explicitly incorporates both transit agency cost and passenger level of service. More specifically, the model assumes: (i) a fixed-route bus schedule; (ii) desired passenger pick-up and drop-off points; (iii) time window constraints for passenger pick-ups, drop-offs, and transfers; and (iv) passenger level of service constraints, including maximum travel times and number of transfers. Using this information, the proposed technique determines which trips are eligible for integrated service using the passenger level-of-service constraints. A schedule is then created for both the passenger trips and the vehicle trips, so that the total cost of service is minimized. The method is illustrated using a case study of transit service in Houston, Texas, showing the possible cost advantages and changes in passenger level of service with integrated service. The contributions of the research include: (i) a new heuristic for scheduling integrated transit trips that accommodates both passenger and vehicle scheduling objectives; and, (ii) an illustrated method for evaluating the operating cost and passenger level-of-service implications of integrated transit service.

Keywords: Public Transit Scheduling; Integrated Transit Service; Coordinated Transit Service; Demand-Responsive Service

ENTIRE REPORT (Adobe Acrobat File – 274KBytes)

Truck Trade Corridors Between the U.S. and Mexico

Miguel Andres Figliozzi and Robert Harrison, University of Texas at Austin, August 2001, 287 pp. (472840-00071-1)

Since the implementation of the North American Free Trade Agreement (NAFTA) in 1994, U.S.-Mexico trade has continued to increase and so have the demands on the transportation system. The purpose of this project was to identify U.S.-Mexico trade corridors and determine the characteristics of truck traffic in these corridors, allowing for the provision of methodologies and figures leading to an increased understanding of NAFTA impacts on transportation.

In this report, available data were analyzed to discern main U.S.-Mexico truck trade corridors and to estimate truck volumes. Several maps and tables of data were produced, as well as observations linking various areas of NAFTA truck trade. The capacity, congestion, performance, and operation of NAFTA-related truck corridors and their impacts on the transportation system were also analyzed, specifically within the context of multimodal transportation planning activities.

Because U.S.-Mexico trade is very dynamic and important changes continue to occur, the impacts of NAFTA may be quite extensive. Implementation of a NAFTA monitoring system that would follow trade statistics, corridors, traffic counts, and WIM data would provide a means of anticipating infrastructure problems and guiding investment policies. In addition, monitoring axle loads, truck volumes, and origins and destinations will be beneficial for planning purposes and pavement management on the NAFTA highway network.

Keywords: Truck Trade Corridors, NAFTA Monitoring System, U.S.-Mexico Trade Corridors, NAFTA Truck Trade

ENTIRE REPORT (Adobe Acrobat File – 13.3 MB)

Adaptive Equipment to Enhance Older Driver Performance: A Guidebook

Rodger J. Koppa, with contributions by John M. Holmgreen and April M. Salzmann (TTI) and Roger E. Levy (Texas Center for Disability Studies), Texas A&M University, August 2001, 57 pp. (167124-1)

As all drivers age, limitations in performance as drivers becomes more prevalent. These limitations include visual losses, diminished range of motion, various musculoskeletal disorders. Decrease in ability to timeshare functions has also been noted. Rehabilitation engineering has addressed adaptive equipment from the standpoint of definite physical disabilities and eliminating the handicap arising from such disabilities, but such technology also has application to people who may not be classified as disabled per se, but could use adaptive approaches to minimize the age-related limitations in performance. This Guidebook identifies applicable and practical equipment to improve older driver performance that arises from the automotive adaptive equipment field. Sections of the Guidebook describe adaptive equipment as part of assistive technology, and its application to any older driver. Criteria are given on choosing the right vehicle that is best designed to accommodate the older driver. For new and existing personal vehicles visibility and auditory enhancements are then described. An approach to control adaptation as applicable for relatively undisabled but possibly limited older drivers is then discussed, followed by guidelines for selecting equipment to enhance access to the vehicle. The Guidebook concludes with a brief discussion of Intelligent Transportation Systems and their implications for older drivers. Each chapter of the Guidebook contains resources for readers to obtain more product information and technical data.

Keywords: Older, Driver, Automotive, Adaptive, Disabilities

ENTIRE REPORT (Adobe Acrobat File – 16.5 MB)

Proceedings from the Texas Rural Transportation Conference Transportation and Tourism Track

Katherine F. Turnbull, Texas A&M University, July 2001, 27 pp. (167704-1)

This report documents the proceedings from the Transportation and Tourism Track at the Texas Rural Transportation Conference held in College Station, Texas on February 21, 2000. The Conference was sponsored by the Texas Transportation Institute, the Southwest Region University Transportation Center, and the Texas A&M University Recreation, Parks and Tourism Sciences Department.

The proceedings summarize the presentations from the opening session and the breakout sessions. The two breakout sessions addressed tourism and transportation in Texas and Texas tourism trails. The main topics covered by speakers are highlighted. The proceedings also present the key issues and research needs relating to transportation and tourism in the state identified by the conference participants.

Keywords: Transportation Tourism, Transportation Trails, Cultural Tourism, Heritage Tourism

ENTIRE REPORT (Adobe Acrobat File – 407KBytes)

Examining Information Needs for Efficient Motor Carrier Transportation by Investigating Travel Time Characteristics and Logistics

William L. Eisele and Laurence R. Rilett, Texas A&M University, June 2001, 318 pp. (473700-00005-1)

This report presents both survey results and field data analysis investigating information needs for motor carrier logistics. Relevant research in the area of estimating travel time characteristics is presented. Survey results of trucking companies and trucking professionals are also included. Although the sample size is low, useful insight is obtained from the survey respondents and is discussed in the report.

The accurate estimation of travel time data is valuable for a variety of real-time and off-line transportation applications including motor carriers. This report includes methodologies for estimating corridor travel time mean and variance from field data collection at two test sites. The test sites are two limited-access freeway corridorsñone instrumented with AVI antennas and one instrumented with dual inductance loop detectors at 0.5-mile spacings. The estimates using the ITS data were compared to simultaneous instrumented test vehicle and commercial vehicle travel time data.

A procedure was outlined for using the loess nonparametric statistical technique to obtain corridor travel time mean and variance estimates from each ITS data source, commercial vehicles, and instrumented test vehicles. The estimates from each data source were then aggregated to five minutes, and the ITS data source estimates were compared to the commercial vehicle and instrumented test vehicle corridor travel time estimates. In addition, a methodology for testing the accuracy of instrumented test vehicle drivers along a corridor was developed.

The research demonstrates that commercial vehicles have statistically different travel time mean and standard deviation than AVI-equipped, vehicles which suggests it may be beneficial to provide traveler information in real-time for commercial vehicles. It was also found that AVI-equipped vehicles were not statistically different than the instrumented test vehicles and that an AVI system with an adequate number of tag reads could replace traditional data collection methods. By comparing inductance loop travel time estimates to the commercial vehicle and test vehicle data sources, the research quantifies how aggregated inductance loop detector travel time estimates do not capture the travel time variance characteristics of individual vehicles.

Keywords: Travel Time Estimation, CVO, Test Vehicle, Inductance Loops, AVI, Motor Carriers, Trucks, Logistics

ENTIRE REPORT (Adobe Acrobat File – 20.2 MB)

Economic Evaluation of Transit Bus Design Standards

Mark Hickman and Ranhee Jeong, Texas A&M University, June 2001, 45 pp. (1674