Vehicle Trip Reduction Impacts of Transit-Oriented Housing

A survey of 17 transit-oriented developments (TOD) in five U.S. metropolitan areas showed that vehicle trips per dwelling unit were substantially below what the Institute of Transportation Engineer’s Trip Generation manual estimates. Over a typical weekday period, the surveyed TOD housing projects averaged 44 percent fewer vehicle trips than that estimated by the manual (3.754 versus 6.715). Vehicle trip rates of transit-oriented housing projects were particularly low in metropolitan Washington, D.C. and Portland, Oregon, both known for successful TOD planning at the regional and corridor levels. Trip rates also generally fell as neighborhood densities increased. Local officials should account for the lower automobile use of those residing in TOD housing through such measures as traffic impact-fee adjustments and reduced offstreet parking requirements