An investigation of induced travel at mixed-use developments

• Main Author: Sperry, Benjamin Robert
• Other Authors: Burris, Mark W.
• Format: Others
• Language: en_US
• Published: 2010
• Subjects: Transportation Planning; Mixed-Use Developments; Induced Travel; New Urbanism; Neotraditional Neighborhood Development; Legacy Town Center
• Online Access: http://hdl.handle.net/1969.1/ETD-TAMU-2695; http://hdl.handle.net/1969.1/ETD-TAMU-2695

Existing literature suggests that mixed land-use developments have the potential to reduce traffic by “capturing” some trips internally and providing a pedestrian-friendly environment to facilitate walking for some trips. However, these elements which are meant to provide the traffic-reducing benefits also reduce the overall cost of travel, thereby increasing the total amount of travel. This “induced” travel has implications for the site planning process, which assumes that all internal trips are replacing trips on the external street network. In this investigation, travel survey data were analyzed to determine the nature and extent of induced travel at mixed-use developments. The study site was a 75-acre suburban infill mixed-use development in Plano, Texas. Features of the study site included a diverse land-use mix, a grid-style street layout, and pedestrian-oriented streetscapes. The travel survey was administered as an interview of persons exiting buildings at the site and gathered information about two trips made by the respondent, including whether the trip made at the time of the interview was induced. A trip was considered induced if the respondent would not have made the trip if it had required travel outside of Legacy Town Center. Analysis found that in the morning, four percent of all trips at the study site were induced; in the afternoon, about one-quarter of all trips were induced. Induced trips accounted for one-eighth of internal trips in the morning and forty percent of internal trips in the afternoon. Most internal trips made in an automobile were replacements for off-site travel while most trips made on foot were induced. Based on this study, it is evident that some internal trips at mixeduse developments are not “captured” from external streets, but represent additional trips, induced by travel cost savings in the mixed-use environment. However, it is demonstrated that, even with this additional travel, mixed-use developments still contribute to a reduction in overall vehicle-miles of travel. Stakeholders are encouraged to consider these findings when evaluating new land-use policies or the traffic impacts of proposed mixed-use developments.