Transit Utilization and Traffic Congestion: Is There a Connection?

This policy study provides a statistical analysis of the relationship between transit utilization and traffic congestion. Data from 74 United States urban areas from 1982 to 2007 was analyzed. In addition, case studies from Chicago, Dallas, Houston, Los Angeles, New York City, Portland, and Washington D.C are provided. Traffic congestion was measured using the Texas Transportation Institute’s Travel Time Index (TTI). Transit utilization was measured using annual transit unlinked trips per capita and annual transit passenger-miles per capita. In addition to transit trips, this study also looks at the effect of vehicle-miles traveled on traffic congestion. The study finds that transit utilization does not appear to reduce congestion and that reducing the number of vehicle-miles traveled can lead to a reduction in congestion.