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SWUTC Ph.D. Candidate Assistantship Project Description

Methodologies for Developing Driveway Functional Areas for Urban Corridor Access Management

University: Texas A&M University

Principal Investigator:
Yanfen Zhou
Zachry Department of Civil Engineering

Faculty Supervisor:
Dr. Gene Hawkins
Zachry Department of Civil Engineering
(979) 845-9946

Funding Source: USDOT Funds

Total Project Cost: $37,592

Project Number: 600451-00051

Date Started: 10/1/15

Estimated Completion Date: 8/31/15

Project Summary

Project Abstract:
This proposal describes a research plan to develop a qualitative and quantitative method of defining driveway functional areas that provide an upstream and downstream functional distance on both sides of the roadway in the vicinity of driveways. The driveway functional area will be incorporated into access spacing determination. The final methodology will enable transportation agencies to establish access spacing standards for various types of driveways and roadways with different geometric and traffic characteristics.

Project Objectives:
The goal of this dissertation is to develop a methodology that defines the functional area of a driveway and then can be incorporated into access spacing standards. The research has the following objectives:

  1. Review current practices and design criteria for driveway location and driveway spacing and identify whether current driveway spacing determination metrics are appropriate; review functional intersection area for both upstream and downstream of an intersection and identify how the functional area of a driveway should differ from a signalized intersection and how this functional distance should be calculated;
  2. Using data collected from the field, conduct conflict analysis and study driveway activities and driver maneuver behaviors upstream and downstream of the driveway on both sides of the major street (including lane changing and deceleration, turning movements or waiting time, etc.); investigate what and how traffic conditions and road features influence driver behaviors.
  3. Conducting microscopic simulation study to investigate the influence of driveway vehicles on through traffic on the major roadway by studying the maneuver behavior of through traffic, for example, when and where through vehicles respond to driveway activities such as speed reduction or lane changing to better understand and develop the definition of driveway functional area. The simulation study will also be used to analyze driveway functional area under various scenarios with different design features.
  4. Using data from objectives 2 and 3, develop a statistical model to calculate the functional distance of a driveway using key variables of traffic data and roadway and driveway geometric data. Factors should include urban corridor and driveway traffic data and roadway information, including land use, driveway treatment, median treatment, geometric data, traffic volume, speed, driveway density, and other factors that may affect driveway activities.
  5. Use microscopic simulation to evaluate driveway functional area derived from the developed methodology by comparing operational performance with current commonly used access spacing criteria.

Task Descriptions:

Task 1Literature Review:
The literature review will summarize current knowledge related to the proposed dissertation and study methodologies.

Task 2Conduct Data Collection:
The field data that will be used in this study has been collected as part of a large data collection effort for NCHRP Project 07-23, Access Management in the Vicinity of Interchange. The author has been actively working on this project and has significantly participated in the data collection effort.

Task 3Data Reduction:
Data reduction should be completed in the following three specific tasks:

  1. Conflict points: investigate conflict points that occur between driveway traffic and roadway traffic in both travel directions. Identify locations where conflicts occur the most frequently for each access type. Conflict types should include crossing, merging, diverging, weaving, stopping and queueing, and opposing through and left turn (1).
  2. For egress/ingress driveway traffic: speed data, travel trajectory, moving distance (acceleration distance, deceleration distance, lane changing and weaving distance, etc.)
  3. Influence distance on traffic stream: speed/ deceleration rate change trajectory and locations where the following through vehicles on the major street responds to driveway activities and begins to slow down or change lanes.

Task 4Data Analysis:
The data analysis task consists of the following three components: conflict analysis and safety assessment, develop the definition of the driveway functional area, and regression analysis.

Task 5 – Simulation Analysis:
Besides simulation analysis in Task 4 to study maneuver behaviors of through traffic influenced by driveway traffic, the author will also use microscopic simulation as a supplemental method to analyze driveway functional areas under various scenarios with different design features. Since no field data is available for a RIROLO configuration, the author will develop a microscopic simulation model from a ground proofed full movement configuration to study driveway traffic movements and their influence on the traffic stream.

Task 6 – Evaluation:
The final part of the research plan is to evaluate the methodology of defining driveway functional area that is developed. Based on collected field data and travel time studies, the author will develop and validate simulation models for study corridors with existing roadway features and driveway locations. The author will then make adjustment to the existing models and develop alternative models by using driveway spacing criteria based on proposed driveway functional areas and alternative models by using various driveway spacing criteria that are discussed in the background section. The validation process will compare the traffic operational performance measurements (speed, delay and travel time) of alternative models with existing models.

Task 7 – Report Findings:
The author will report findings developed by this research.