The University of Utah
College of Architecture + Planning

Trip and Parking Generation at Transit-Oriented Developments: Phases I & II

This project aims to help planners accurately estimate trip and parking generation at transit-oriented developments (TODs). This project is funded by National Institute of Transportation and Communities (NITC). The research team for this project includes principal investigator Dr. Reid Ewing, as well as PhD students Guang Tian and Torrey Lyons.

The decision on how best to allocate land around transit stations is a debated topic, with transit officials often opting for park-and-ride lots over active uses such as multifamily housing, office, and retail organized into TODs. Providing large park-and-ride lots has been the default strategy to maximize transit ridership in the short-run. But is it the best strategy in the long run? The debate continues when land is developed, with officials usually assuming that TODs require the same number of parking spaces as conventional development. In such cases, many officials assume that transit stations near TODs require the same number of park-and-ride spaces as non-TOD stations without considering the possibility that much of the travel demand is captured internally and TODs themselves generate much of the transit demand.

Balancing the amount of parking at TODs with the need to create a pedestrian-friendly environment and encourage mixed-use development can be complicated. We define TODs using seven criteria and identify the best TODs that meet these criteria. It is our intention to test whether TODs generate as many vehicle trips as the Institute of Transportation Engineers (ITE) Trip Generation manual estimates, and whether they need as much parking as the ITE Parking Generation manual suggests.

Consulting partners NelsonNygaard and Fehr & Peers assisted in data collection, analysis, report and article writing. Specifically, they conducted the parking supply and occupancy studies and building access counts along with intercept surveys. We used this data to analyze travel modes and parking use allowing us to develop numerical models of trip and parking demand as well as recommendations for land use and parking policies at new TOD developments.

Results from this research in five mixed-use TOD projects (The Englewood, Colorado; The Wilshire/Vermont TOD; Oakland, California’s Fruitvale Transit Village; The Redmond, Washington; and Rhode Island Row in Washington, D.C.) found that peak parking occupancy was less than 50 percent of ITE parking supply guidelines.


Read more in our Final NITC Report. (January 2017)

Read more in Smarth Growth America’s report Empty Spaces. (February 2017)

Read our article in Landscape and Urban Planning (December 2016)

Additional case studies have been produced in different regions:

Read our case study of the Orenco Station TOD in Portland

Read our comparative case studies of Orenco Station TOD and Station Park TAD (transit-adjacent development) in the Salt Lake City Region