The study, Transit Utilization and Traffic Congestion: Is There a Connection? by Thomas A. Rubin and Fatma Mansour, found a positive correlation between public transit utilization (per capita transit trips and passenger-miles) and traffic congestion intensity (increased Travel Time Index) among U.S. cities. They claim this demonstrates that public transit is ineffective at reducing congestion. This report critiques their study. Their analysis contains omissions and biases which tend to underestimate the congestion reductions provided by high quality transit: it uses congestion intensity rather than congestion costs indicators, and so it ignores the congestion avoided by users of grade-separated transit; it fails to account for confounding factors such as city size, density and employment rates; it includes all regional transit use although only high quality, grade separated service on major urban corridors is expected to reduce congestion. Other studies which account for these factors indicate that high quality transit can reduce congestion. As a result of their omissions and biases, Rubin and Mansour’s study provides no guidance for answering policy questions such as whether appropriate transit service improvements can help reduce congestion, and how to maximize the value of transit investments. (Author/publisher)
Samenvatting