Study shows Portland-area TODs generate fewer car trips, increase in transit use

A new report from Portland State University’s (PSU) Transportation Research and Education Center (TREC) highlights that fewer car trips than standard estimates suggest are generated around Portland-area transit-oriented developments (TODs), especially at sites where affordable housing was included.

The report, "Portland Metro Transit-Oriented Developments (TODs): 2024 Resident Survey Findings," continues off a long-running PSU study that was designed to track TOD residents since 2005. Researchers surveyed residents at TODs constructed between 2018 and 2023 across eight Oregon cities: Portland, Beaverton, Cornelius, Milwaukie, Gresham, Tigard, Hillsboro and Happy Valley. 

Most of the TODs and units surveyed in 2024 are designed for households with 30%–80% of the local median income. Twenty-eight of the 36 surveyed sites were categorized as affordable housing units.

The survey was adapted with new questions that explored changes in travel patterns due to the pandemic, including work-from-home availability and online shopping trends.

Key findings

• Fewer cars, more transit: TOD residents drove less than initially predicted. Car trips per housing unit were approximately 50% of the standard estimates, and for affordable housing sites, car trips were only about 20%-25% of expected estimates.
• Sustainable travel habits: Less than 50% of all trips were by vehicle. A total of 28% of residents relied heavily on transit, 19% on walking and 2% biking. For commuting, the report found that these developments far surpassed the 7% average for Portland-area commuters with 41% using transit regularly for their commutes.
• Zero-car households: Half of residents at sites primary designed as affordable don’t own a vehicle. These households take even more transit, walking, and biking trips.
• Behavior changes: About a fifth of residents have given up or are considering giving up a vehicle because of the walkability and transit-friendly design of the neighborhood.
• Housing priorities vary: The report also found that affordable housing residents prioritize transit access, while market-rate residents focus on amenities, neighborhood quality and the availability of parking.

Opportunities for great impact

The report highlighted options to further encourage the use of transit, like expanding access to reduced fare passes for eligible residents and better integration of affordable TOD sites with light-rail lines.