Giving pedestrians a seven-second head start at traffic lights, known as Leading Pedestrian Intervals (LPIs), has led to a 33 percent reduction in pedestrian injuries at New York City intersections. This is according to a study by researchers at Columbia University Mailman School of Public Health.
The research analyzed data from 6,003 intersections, marking the largest dataset to date evaluating LPI effectiveness. The reduction in pedestrian injuries was consistent across all intersection types, with fatal pedestrian crashes dropping by 65 percent during daylight hours.
LPIs allow pedestrians to begin crossing before vehicles get a green light to turn, typically offering a 7- to 11-second lead depending on the intersection size. “The idea is to give pedestrians time to reach the center of the intersection where they’re more visible,” said the lead author, PhD, assistant professor at Columbia Mailman School. “Most pedestrian-vehicle crashes happen near the curb, where drivers are less likely to see people crossing.”
The study evaluated intersection-level injury risk from 2013 to 2018 using geographic data from NYC Open Data and Vision Zero initiative. Of the intersections studied, 2,869 had LPI treatments installed.
New York City was an early adopter of Vision Zero program aimed at reducing traffic-related injuries and deaths. LPIs are central to this strategy alongside other measures like speed humps and turn-calming treatments.
Globally, road traffic crashes cause over 1.35 million deaths annually. In the U.S., over 68,000 pedestrian deaths occurred between 2011 and 2020—many in large cities like New York.
“As someone who lives in the city, it is good to know that interventions like LPIs led by NYCDOT are making pedestrians safe,” noted co-author Siddhesh (Sid) Zadey.
“LPIs are one of the most affordable and scalable traffic safety interventions,” Morrison added. “A 7-second delay for drivers can mean life or death for pedestrians.”
Other co-authors include Leah Roberts, Brady Bushover, Arianna Gobaud, Christina Mehranbod, Carolyn Fish, Xiang Gao, Evan Eschliman, and Dana Goin—all from Columbia University Mailman School of Public Health.
Funding was provided by CDC’s National Center for Injury Prevention and Control (Grant R49CE003094) and National Institute on Drug Abuse (Grant T32DA031099).
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