2025 Theses Doctoral

Essays in the Economics of Transportation

Yang, Natalie J.

The essays in this dissertation study the economics of urban transportation policies. The first chapter investigates how voters form beliefs and opinions on congestion pricing and why they change those beliefs and opinions once they see the policy in place. Using a panel of surveys conducted in New York City in the months before and after the city implemented congestion pricing in January 2025, I find that the introduction of congestion pricing led to a 3 percentage point increase in support, from 38 percent to 41 percent. At the same time, familiarity and knowledge of congestion pricing increased during this period, which appears to at least in part drive the increase in support. Voter opinion on congestion pricing seems to be driven less by personal experience with the policy and more by beliefs about the effectiveness of the policy in general.

Using a randomized information intervention experiment, I find that survey respondents who were shown that congestion pricing reduced driving times were 9 percentage points more likely to support the policy. The information treatment was particularly effective on respondents for whom the information was novel, which is consistent with Bayesian updating. The second chapter examines a similar question, but takes as its setting congestion pricing in London. I show that ex ante voter support is {inversely related} to the predicted benefits of the policy: a 1 percent increase in the expected welfare gains of congestion pricing corresponds with a 4.5 percent {decrease} in the share of support for the policy. I argue that this result can be explained by "egocentric bias," which leads drivers who switch to public transit under congestion pricing to underestimate the effect of the policy on traffic reduction, thereby underestimating its welfare effects. I also find that education significantly increased the accuracy of voters' beliefs about congestion pricing, which lends further support to the idea that inaccurate understanding of the effect of the policy is at the root of voter opposition.

The third and final chapter develops a novel method for estimating demand in the presence of stockouts and applies it to study New York City's bike-share system. The results indicate that on average, demand for bike-share trips would be twice as high if stockouts could be eliminated. During periods of high demand, more than 60 percent of commuters whose first-choice bike-share trip is out-of-stock choose not to take bike-share at all rather than substitute to an alternative in-stock trip. These results have implications for urban transportation and the environment. Stockouts are a barrier preventing bike-shares from serving as a viable mode of sustainable urban transportation.