NYC: Pedestrian Injuries Drop with Longer Crossing Times

New York City’s bustling intersections, often a source of anxiety for pedestrians, have seen a significant improvement in safety thanks to a simple adjustment: giving walkers a head start. A recent study from Columbia University’s Mailman School of Public Health reveals that implementing Leading Pedestrian Intervals (LPIs) , which allow pedestrians to begin crossing the street a few seconds before cars get a green light , is linked to a 33% reduction in pedestrian injuries across the city.

The study, published in Nature Cities, analyzed data from over 6,000 intersections, making it the most comprehensive evaluation of LPI effectiveness to date. The results consistently showed a decrease in pedestrian injuries, regardless of the intersection’s specific characteristics. Notably, fatal pedestrian crashes decreased by a staggering 65% during daylight hours.

“The idea is to give pedestrians time to reach the center of the intersection where they’re more visible,” explains Christopher Morrison, Ph.D., assistant professor of epidemiology at Columbia Mailman School and the study’s lead author. “Most pedestrian-vehicle crashes happen near the curb, where drivers are less likely to see people crossing.”

LPIs typically provide a 7- to 11-second head start, depending on the intersection’s size. This brief window allows pedestrians to establish their presence in the crosswalk before vehicles begin making turns, increasing their visibility and reducing the risk of collisions.

New York City has been at the forefront of the Vision Zero initiative, a global movement aimed at eliminating traffic-related fatalities and injuries. LPIs are just one component of the city’s broader strategy, which also includes measures like speed humps and turn-calming treatments.

The implications became clear later. I spoke to a resident of the Upper West Side, Maria Rodriguez, who walks her children to school every day. “You never really think about those few seconds,” she said, “but now that I know they can make such a big difference, I feel a little safer.” She added, noting increased congestion at some intersections: “We just need to make sure they get implemented right. I saw a few confusing light cycles just last week.”

To better understand the context of this success, here are some key elements of the LPI program and its impact:

• Data Driven: Researchers analyzed injury data from 2013-2018, leveraging NYC Open Data and Vision Zero statistics to pinpoint high-risk areas.
• Targeted Approach: The study focused on injuries within 100 feet of signalized intersections, categorizing intersections based on their proximity to LPI installations.
• Scalable Solution: LPIs are relatively inexpensive to implement, making them an attractive option for cities seeking to improve pedestrian safety without major infrastructure overhauls.

However, not everyone is convinced that LPIs are a perfect solution. Some drivers have taken to social media to express frustration over the slightly longer wait times at intersections. On X.com, one user wrote: “These delays are ridiculous! Now I’m late for everything!” Another commenter on a local Facebook group complined: “It’s only a few seconds, people. Get a grip.”

Despite the occassional grumbles, the data paints a clear picture: LPIs are saving lives. In the grand scheme of global road safety, where traffic crashes cause over 1.35 million deaths annually, interventions like LPIs represent a crucial step forward. In the United States alone, over 68,000 pedestrian fatalities occurred between 2011 and 2020. Finding effective and affordable ways to protect pedestrians is more critical than ever.

Siddhesh (Sid) Zadey, a doctoral student in Epidemiology at Columbia Mailman School and co-author of the study, emphasized the importance of the research: “As someone who lives in the city, it is good to know that interventions like LPIs led by NYCDOT are making pedestrians safe.”

Morrison echoed this sentiment, highlighting the scalability of LPIs: “LPIs are one of the most affordable and scalable traffic safety interventions. 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.” He further noted that, depending on the intersection, adjustments might be needed to find the optimal balance between pedestrian safety and traffic flow. “It’s not one-size-fits-all,” he admited. “Each intersection requires careful consideration.”

The success of LPIs in New York City offers a compelling case study for other urban centers seeking to improve pedestrian safety. While some drivers may experience minor inconveniences, the significant reduction in injuries and fatalities speaks volumes about the effectiveness of this simple yet powerful intervention. The hope is that this study will encourage other cities to adopt LPIs and prioritize the safety of their most vulnerable road users.