ESSAYS ON TRANSPORTATION ECONOMICS IN NEW YORK CITY

Abstract

Traffic congestion is one of the most important challenges facing large urban areas. It increases commuting time, worsens air pollution, and lowers the overall efficiency of the urban transportation system. New York City provides a useful setting to study these issues because it is one of the largest and most congested cities in the United States, with a dense road network, extensive public transit system, and large daily commuting flows. A central policy question is how cities can reduce congestion and improve urban mobility. Common approaches include congestion pricing, expansion of public transit, and infrastructure investment to maintain or improve road capacity. However, whether these policies work, how large their effects are, and who benefits or loses from them remain empirical questions.

Chapter 1 studies New York City’s congestion pricing program, the first large-scale congestion charge implemented in the United States. I estimate a structural model of travel mode choice and embed it in a congestion feedback framework to evaluate how the toll affects mode choice, traffic speeds, welfare, and distributional outcomes. The chapter also emphasizes the importance of revenue use. Congestion pricing raises toll revenue, and the welfare and equity effects depend on whether the revenue is returned to residents, used to subsidize public transit, or invested in transportation infrastructure.

Chapter 2 examines public transit expansion as a potential congestion-relief policy. I study the opening of three new stations on the Second Avenue Subway extension and estimate its effect on nearby road congestion. Using hourly traffic speed data, I combine a panel event-study design with a difference-in-differences framework. The results show that traffic delay declined on road segments close to the new stations after the opening, suggesting that public transit expansion can reduce congestion, although the benefits are geographically concentrated.

Chapter 3 studies road infrastructure investment from a different angle. Road construction is necessary for maintaining road quality and long-run capacity, but construction activity can also create short-run congestion costs through lane closures, detours, and temporary reductions in road capacity. Using high-frequency traffic speed data and detailed construction records from Manhattan, we estimate how active road construction projects affect traffic speeds and translate these effects into commuter costs. The results show that construction-related congestion can impose meaningful costs on urban commuters, especially near already congested road segments.

Taken together, the three chapters show that congestion policy involves tradeoffs across efficiency, equity, and implementation. Congestion pricing can reduce vehicle travel and raise revenue, but its distributional effects depend on how the revenue is used. Public transit expansion can reduce congestion, but the benefits may be localized. Road infrastructure investment is necessary, but construction itself can temporarily worsen congestion. These findings suggest that effective urban transportation policy requires evaluating not only whether a policy reduces congestion, but also how large the effect is, where it occurs, and how the costs and benefits are distributed.