A 7-second delay for drivers resulted in a 33 % reduction in total pedestrian injuries – both fatal … More
Giving pedestrians a 7-second head start at traffic lights can reduce injuries and deaths by a third. The traffic safety intervention can mean the difference between life and death for walkers, and is one of the most affordable and do-able measures to implement that could be adopted more widely.
Those are the main findings of a new study announced on Friday by the Columbia University Mailman School of Public Health, published in “Nature Cities,” that found that a 7-second delay for drivers resulted in a 33 % reduction in total pedestrian injuries – both fatal and non-fatal — at New York City intersections,
“The idea is to give pedestrians time to reach the center of the intersection where they’re more visible,” Christopher Morrison, lead author of the study and assistant professor of Epidemiology at Columbia Mailman School, said in a statement. “Most pedestrian-vehicle crashes happen near the curb, where drivers are less likely to see people crossing.”
The delays or longer head starts, called “Leading Pedestrian Intervals (LPIs), ” allow walkers to begin crossing before vehicles get a green light to turn, typically offering a 7–11 second lead, depending on the intersection size.
For the study, “Effectiveness of leading pedestrian intervals for city walkers’ safety,” researchers analyzed 6,003 intersections in New York City from 2013-2018 in what they said is the largest dataset to date evaluating the treatment’s effectiveness and risk. Of the intersections assessed, nearly half had leading pedestrian interval treatments installed.
Researchers focused on pedestrian injuries occurring within 100 feet of a signalized intersection.
The reduction in injuries to walkers was consistent across all intersection types, according to the study, with the most pronounced impact seen during daylight hours, when fatal pedestrian crashes dropped by 65 %.
“As someone who lives in the city, it is good to know that interventions like LPIs led by NYCDOT are making pedestrians safe,” Siddhesh Zadey, a co-author and doctoral student in Epidemiology at Columbia Mailman School, said in a statement.
The report noted that New York City was an early adopter in the United States of the Vision Zero or Safe System approach to road safety and design that takes human error into account, first put into effect in Sweden in the 1990s.
The goal of the initiative is to eliminate all road deaths and serious injuries by creating multiple layers of protection, so if one fails, the others will provide a safety net to lessen the impact of a crash. Improvements are designed to result in: safer people, safer roads, safer vehicles, safer speeds and better post-crash care.
As part of the safety net, leading pedestrian intervals—alongside other low-cost measures like speed humps and turn-calming treatments like rubber speed bumps— “are central to the city’s pedestrian safety strategy,” researchers noted.
“LPIs are one of the most affordable and scalable traffic safety interventions,” added Morrison, the lead author of the study. “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.”
For more information and to access the study, click here and here.