Recent study supports the case for transit oriented development

By Chris Spahr

The total effect of transit on VMT may be much greater than it appears on the surface. Using a transit multiplier, Reid Ewing and Shima Hamidi estimated that the Portland Westside Max light rail transit (LRT) extension indirectly reduces VMT by three vehicle miles for every one vehicle-mile reduction attributed to ridership increases.  The indirect reduction in VMT can be attributed to compact land uses near stations and increased walking. Even those who live near transit but do not use it may drive less due to the compact, mixed-use neighborhoods created by transit and supportive public policies. Local governments, Portland Metro (the regional government), TriMet (the transit operator) and the state of Oregon have all taken steps to encourage transit-oriented development.

The Westside LRT was completed in 1998. Using household travel surveys from 1994 and 2011, the researchers conducted a longitudinal study of a section of the LRT extending for 15 miles with 17 stations. This corridor was compared to the SW Pacific Highway Corridor, which had characteristics similar to what may have happened in the Westside transit corridor in the absence of LRT. The study was published in the Journal of the American Planning Association on August 25.

Chris Spahr is a Graduate Assistant with SSTI.