SWUTC Research Project Description
Title of Project: Trip Internalization and Mixed-Use Development: A Case Study of Austin, Texas
Project Number: 169207
Principal Investigator:
Ming Zhang
(512) 471-0139
P.I. Affiliation: University of Texas at Austin
zhangm@mail.utexas.edu
Project Monitor:
Daniel Yang, Ph.D.
Program Manager of GIS, Demographic Forecasting and Travel Demand Modeling
Capital Area Metropolitan Planning Organization
One Texas Center
505 Barton Springs Rd., Suite 700
Austin, TX 78704;
Ph: 512-974-6423; Fax: 512-974-6385
Project Status: Active
Date Started: 9/1/08
Estimation Completion Date: 8/31/09
Estimated Cost - Current Fiscal: $30,000
Estimated Cost - Total Planned: $30,000
Project Summary:
Project Abstract:
Many MPOs in Texas are promoting mixed-use development as an alternative to the convention of single-use, free-standing land uses. The widespread interest in mixed-use development lies in the expectation that the alternative development reduces regional traffic by internalizing travel—trips are captured on site as a result of different urban functions being integrated internally in the development zone. Determining the internal rate of capture, however, has been a challenge. The Institute of Transportation Engineers (ITE) publishes trip generation reports. Yet the ITE trip tables are calibrated predominately based on studies of single-use, free-standing sites. For practical application of the published trip rates, ITE thus recommends collection of additional data. Proper identification of the internal rate of capture has important implications. With more reliable estimates of trip rates, MPOs can improve their long-range travel demand forecasts and gain better understanding of the transportation impacts of policy or development initiatives such as those mentioned above. On the project basis, developers would like to see liberal estimates of internal rates for the interest of minimizing impact fees. Local governments would like to use conservative estimates of the rates to ensure sufficient public infrastructure being accompanied with the new development. To determine the rates fairly and objectively, adequate research is necessary to gather and analyze empirical data on the attributes of mixed-use development and its influence on the level of trip internalization. The proposed study is aimed at contributing to the field through a case study of the Austin, TX area.
Project Objectives:
Task Descriptions:
Task 1. Identify sites of mixed- and non-mixed use development in Austin, TX
This will be done by telephone calls and/or office visits with planners and professionals of all local communities in the Austin area. They will be asked for information on locations, types, and boundaries of development projects that fit the definition of mixed-used development. A sample of non-mixed-use development will also be recorded as a control group for analysis.
Task 2. Digitize identified sites in GIS and derive urban form measures
Typical urban form measures to be derived include: population and job density, entropy of land use mix, street density and connectivity, block size and sidewalk continuity, transit supply (stop/route density and service frequency), along with others.
Task 3. Geocode Samples Using GIS
Locations of trip ends/activity destinations of the sample from the 2005 Activity Travel Survey in the Austin area will be identified using GIS. Internal trips that have both trip origins and destinations located in the same zone will be identified.
Task 4. Calculate internal trip rates and analyze internal trip characteristics
Trip characteristics, including purpose, distance, and travel mode, will be compared with those in non-mixed-use development.
Task 5. Estimate regression/choice models
Internal trip rate, distance, and mode choice as functions of i) traveler personal and household characteristics, ii) transportation system characteristics, and iii) urban form characteristics of mixed use sites and trip ends in the region will be used to estimate regression/choice models.
Task 6. Prepare final report
The findings of trip internalization as a function of urban form characteristics of mixed-use development will be included in a final report. The transferability of the study method and the findings to other metropolitan areas in Texas will also be included in the final report.
Index Terms:
Mixed use development, Case studies, Land use planning, Land use, Development, Travel demand, Policy making, Trip purpose, Research projects