Date of Award

Spring 5-2-2019

Document Type


Degree Name

Master of Arts (MA)



First Advisor

Jonathan Conning

Second Advisor

Partha Deb

Academic Program Adviser

Randall Filer


I evaluated the impact of the phased introduction of Leading Pedestrian Interval Signals (LPIs) on collision and injury outcomes at 12,987 signalized traffic intersections in New York City over the course of 25 quarters from 2012 to 2018. An intersection is treated when a LPIs is installed to give pedestrians lead time to cross the street before vehicles are allowed to move. Outcomes from NYPD’s Motor Vehicle Collisions data were matched to signalized intersections. I hypothesize that LPIs would reduce collisions and reduce injuries for pedestrians at intersections. A difference in difference fixed effects panel regression was used to identify the causal effect of introducing LPIs. This approach accounts for the problem that unobserved heterogeneity that might bias results in simpler regression approaches. The analysis suggests that the introduction of LPIs decreased quarterly collision counts by 5.45% and decreased the quarterly number of pedestrians injured by 14.7% over the same intervention period. LPIs appears to be effective in reducing both collisions and injuries.


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