Leading Pedestrian Intervals Significantly Reduce NYC Traffic Injuries

In a groundbreaking study by researchers at Columbia University Mailman School of Public Health, introducing Leading Pedestrian Intervals (LPIs) at traffic signals in New York City has been shown to reduce pedestrian injuries by 33%. The study, which analyzed a dataset comprising 6,003 intersections from 2013 to 2018, reveals that the implementation of LPIs, which allows pedestrians a head start of 7 to 11 seconds before vehicles receive a green light, significantly enhances pedestrian safety, particularly during daylight hours where fatal crashes declined by 65%.

The Columbia research team, led by Dr. Christopher Morrison, an assistant professor of Epidemiology, focused on pedestrian injuries occurring within 100 feet of signalized intersections, contrasting locations with LPIs to those without. Morrison explained, "The idea is to give pedestrians time to reach the center of the intersection where they're more visible. Most pedestrian-vehicle crashes happen near the curb, where drivers are less likely to see people crossing."

The study, published in the journal *Nature Cities* in January 2023, is the largest of its kind assessing the effectiveness of LPIs. It found that of the intersections analyzed, 2,869 had LPI treatments installed. The findings are significant considering that globally, road traffic crashes account for over 1.35 million deaths and 50 million injuries annually, with the United States reporting more than 68,000 pedestrian deaths from 2011 to 2020.

New York City has been a pioneer in implementing the Vision Zero initiative, aimed at eliminating traffic-related fatalities. LPIs, along with other cost-effective measures like speed humps and turn-calming treatments, form a central part of the city's strategy to enhance pedestrian safety. Dr. Morrison emphasized the affordability and scalability of LPIs, stating, "A 7-second delay for drivers can mean the difference between life and death for pedestrians. Our findings show they work—and should be adopted more widely."

The study's co-authors included Leah Roberts, Brady Bushover, Arianna Gobaud, and others from Columbia University, highlighting a collaborative effort in addressing public health concerns related to urban traffic safety. Funding for the research was provided by the CDC’s National Center for Injury Prevention and Control and the National Institute on Drug Abuse.

The implications of these findings extend beyond New York City. As urban populations grow and traffic congestion increases, implementing LPIs and similar pedestrian-focused interventions could significantly reduce injury rates in metropolitan areas worldwide. This research not only underscores the importance of pedestrian safety measures but also serves as a call to action for city planners and policymakers to prioritize pedestrian-friendly infrastructural changes in their traffic management strategies.