Subways, Strikes, and Slowdowns: The Impacts of Public Transit on Traffic Congestion
Public transit accounts for only 1% of U.S. passenger miles traveled but nevertheless attracts strong public support. Using a simple choice model, we predict that transit riders are likely to be individuals who commute along routes with the most severe roadway delays. These individuals' choices thus have very high marginal impacts on congestion. We test this prediction with data from a sudden strike in 2003 by Los Angeles transit workers. Estimating a regression discontinuity design, we find that average highway delay increases 47% when transit service ceases. This effect is consistent with our model's predictions and many times larger than earlier estimates, which have generally concluded that public transit provides minimal congestion relief. We find that the net benefits of transit systems appear to be much larger than previously believed.
I thank Ken Small, Lowell Taylor, Matt Turner, and participants at the 13th Occasional California Workshop on Environmental and Resource Economics, the 2012 AERE Summer Conference, Texas A&M, and the University of Houston for valuable suggestions. Any errors in the paper are the author's. The views expressed herein are those of the author and do not necessarily reflect the views of the National Bureau of Economic Research.
Michael L. Anderson, 2014. "Subways, Strikes, and Slowdowns: The Impacts of Public Transit on Traffic Congestion," American Economic Review, American Economic Association, vol. 104(9), pages 2763-96, September. citation courtesy of