Towards Safer Streets: A Quasi-Experimental Analysis of Vision Zero Speed Policies

• In Event: Local Transportation Policies

Abstract

New York City’s Vision Zero initiative encompasses a comprehensive set of traffic safety measures aimed at reducing accidents, injuries, and fatalities. Among its components are targeted speed-limit enforcement policies, including slow zones, speed humps, and automated enforcement systems. This study develops a theoretical framework to model driver behavior under localized enforcement, providing the foundation for an empirical analysis that exploits variation in the timing of policy implementation. Leveraging granular, street-level, daily data on motor vehicle accidents, injuries, and fatalities, I implement an event-study design to estimate the causal effects of these interventions. To further refine the choice of treatment distances in the main specification, I employ nonparametric binscatter regressions that offer a more informed view of where enforcement effects begin and dissipate.

The results uncover a counterintuitive spatial pattern: accident rates tend to increase in very close proximity to treated areas, while injuries and fatalities decline as distance from the intervention site increases. This suggests that enforcement may produce intensified interactions or potentially exacerbated congestion effects locally, while contributing to improved safety outcomes in nearby areas. These patterns appear consistently across different enforcement types, indicating a general behavioral response rather than a policy-specific effect.

These findings challenge the prevailing consensus that increased enforcement uniformly alters driver behavior in beneficial ways. Instead, they point to the possibility that heightened penalties—rather than localized enforcement alone—may be a more effective and less costly tool for discouraging risky driving behaviors. In particular, high-enforcement policies such as automated monitoring systems, when paired with steeper penalties, may serve as a more stringent and scalable deterrent. As cities weigh how to improve roadway safety, this study offers critical evidence on the comparative efficiency of enforcement mechanisms and raises important considerations about cost-effectiveness and behavioral impact in urban transportation policy.

Author

• Daniel Centuriao, West Virginia University
  Presenting Author