Behavioural responses to time-varying congestion pricing: a natural experiment from New York City

Time-varying congestion prices are designed to shift travel away from peak periods, but the timing of toll cut-offs determines whether such adjustment occurs. I study this margin using New York City’s Congestion Relief Zone, which charges $9.00 to enter Manhattan south of 60th Street during peak hours weekdays 5 a.m. to 9 p.m. and on weekends from 9 a.m. to 9 p.m., and $2.25 overnight, creating an identical $6.75 E-ZPass differential at four daily boundaries. Applying a difference-in-discontinuities design to hourly Advan mobile-device visit data comparing Lower Manhattan to Boston, I find that establishment visit starts increase by 5.9% at the weekday 5 a.m. boundary and by 9.2% at the weekend 9 p.m. boundary exactly the two cut-offs where schedule constraints are least binding. Estimates at the weekday 9 p.m. and weekend 9 a.m. boundaries are small and statistically indistinguishable from zero, consistent with high schedule costs at those cut-offs. The asymmetry suggests that toll-boundary placement relative to visitors’ schedule constraints, not price magnitude, governs whether congestion pricing induces retiming.