Working Papers

The Marginal External Cost of Congestion under Nonlinear Speed–Flow Dynamics (with Antonio Bento and Jonathan Hall) [Slides]

Traffic congestion is a major problem in large cities worldwide. This paper uses high-frequency data from the Los Angeles metropolitan area combined with an instrument that varies spatially and temporally to estimate the causal impact of an additional vehicle mile traveled on travel times. Specifically, we exploit the network structure of the Los Angeles highway system and use crashes on close alternative routes as exogenous shocks to traffic demand. To do so, we rely on Google Maps to determine the ideal route and alternatives for over 19,000 real-world commutes. We uncover strong nonlinearities in the speed-flow relationship: below a congestion threshold, an additional trip does not affect speeds, while above the threshold the effect rises to 3.3\%. Using these estimates in a congestion pricing model, we find that an optimal toll of 30 cents per mile during peak hours would more than double average highway speeds while reducing peak vehicles miles traveled by less than 10\%, generating annual welfare gains of $380 million. In contrast, setting an optimal toll without accounting for this nonlinearity leads to welfare losses of $18 million per year, highlighting the importance of incorporating nonlinear speed-flow effects in congestion policy design.

The Impact of Crime Perceptions on Public Transport Demand: Evidence from Six Latin American Capitals (with Juan Gonzalez and Santiago Perez-Vincent) [Draft]

Public transportation systems are central to reducing traffic congestion and urban pollution, yet in high-crime cities, safety concerns may undermine their use. This paper studies how crime affects the demand for public transportation, using three pre-registered experiments with over 5,000 participants across six Latin American capital cities. First, we find that users place a high value on safety in public transportation: reducing crime is valued at over 50\% of the fare. Second, crime reduces the likelihood of choosing public transport over private alternatives, especially among women. For some users, even eliminating fares does not offset the deterrent effect of higher crime. As a result, crime lowers the responsiveness of public transport demand to fare changes, limiting the effectiveness of subsidies in increasing ridership in high-crime settings. Finally, we find that in a budget allocation task, safety concerns do not reduce support for environmental goals, suggesting room for coordinated interventions. Overall, our findings show that crime creates a negative externality on congestion and pollution by limiting shifts to cleaner modes of transport. They underscore the importance of integrating public safety into transport and environmental policy, and highlight the potential for aligning safety and sustainability objectives.

The Effect of Bikesharing on Subway Ridership (2Y Paper) [Draft]

Accessibility to public transportation is a key determinant of transport mode choice. When the distance to or from a public transport hub is beyond walking range, commuters tend to dismiss trip alternatives that require walking to such a hub. This paper examines whether bikeshare systems can improve accessibility to subway stations, thereby expanding their catchment areas and increasing ridership. I study this problem in the context of the City of Buenos Aires, where more than 400 bike stations opened in staggered dates. Following a differences-in-differences design, I estimate that when a bikeshare station opens within 400m of a subway station, the daily volume of passengers of the latter increases by 14.5\%. Moreover, this effect is stronger in non-working days, where I register an increase of 20.7\%. Furthermore, I find that for each additional subway station receiving a nearby bikeshare station, the ridership of its subway line increases by 13.6\%, indicating that the results are not influenced by spillover effects. Finally, I propose a discrete-choice model that could be used to estimate the optimal locations for bikeshare stations, contingent on the availability of additional data. These results highlight the potential of bikeshare systems to boost subway ridership in urban areas, thereby reducing congestion and emissions through the promotion of sustainable transportation.

Work in Progress

The Geography of Opportunity: Effects of Public Transit Subsidies on Labor Markets, Housing and Welfare 

All Cops are Bayesian: How Selection Neglect Drives Statistical Discrimination in Policing (with Juan Gonzalez, Santiago Perez-Vincent and Ervyn Norza) 

Revealed Heterogeneous Exchange Rates: Evidence from Argentina (with Santiago Mosquera)