“When you design roads, that is public health.” (Harvard Public Health)

Quanisha Ball’s commute to work involved catching an employee shuttle just a few blocks from her apartment in Decatur, Georgia. She mapped out the safest route to the shuttle, but there was no avoiding Scott Boulevard, with its seven lanes of traffic and a speed limit of 45 miles per hour. There, on November 17, 2022, she was hit and killed by a car. Police don’t know how fast the car was going, but Ball, who was 31, went airborne, landing outside the crosswalk, while the car had to be towed from the scene.

Ball was part of a 25% jump in traffic fatalities in the United States in the past decade, including a surge in 2020 and 2021. Transportation experts attribute the rising number of deaths to factors such as increased speed limits, the scramble for bigger and heavier vehicles, and the distractions of smartphones. But they also say these deaths are entirely preventable. For instance, Vision Zero, a road safety system widely adopted in Australia, Canada and the European Union, has helped reduce both fatalities and severe injuries. It uses bike lanes, pedestrian walkways, and other design elements to encourage drivers to slow down in places where they share the roads with cyclists and pedestrians.

In the U.S., although cities such as Alexandria, Virginia and Hoboken, New Jersey can point to Vision Zero as helping them eliminate traffic deaths, the program has run into roadblocks. The web of federal, state and local jurisdictions that control decisions about — and funding for — roads is partly to blame. But advocates for safer roads argue that reframing traffic fatalities as a public health crisis would create public awareness and boost support for developing safer infrastructure. They are seeking greater collaboration between transportation engineers and public health experts to change how decisions are made about road design.

“We excuse things that have to do with cars that we don’t with other public health norms,” such as health risks from second-hand smoke, says Tara Goddard, an associate professor in the Department of Landscape Architecture and Urban Planning at Texas A&M University. Goddard’s research shows that an overwhelming majority — almost 84% — of respondents think the risk of serious injury is part of driving (less than 40% feel the same way about work). At the same time, two-thirds said society should not simply accept the consequences of driving.

A public health approach could help transportation engineers promote and execute Vision Zero as a series of systemic changes that address road safety challenges. “When you design roads, when you design routes, when you design even where a bus stop is located or where a transit center is located, that is public health,” says Sophia Peerzada, a public health expert who specializes in traffic safety but is commenting as a private citizen. “Because [design] directly impacts people’s safety on the roads, and their ability to safely get around.”

Road design shapes driver behavior

The majority of traffic fatalities happen in what transportation researchers call high-injury networks. These are typically locations where people walk or bike on or near roads with speed limits set at 35 to 45 miles per hour, and are where the majority of traffic fatalities occur. “Thirty-five miles per hour is really a sweet spot for killing people,” says Patricia Tice, a transportation researcher and founder of the consulting company ProFound Insights. Tice observes that cyclist and pedestrian deaths often occur in what are called “origin-destination pairs,” where a person has to cross a busy street to reach home, work or shopping.

Vision Zero policies focus on identifying high-injury networks and making them safer. A major tenet of the approach, which is backed by research, is that the built environment influences driver behavior. It also holds that road design should account for potential human error, so people aren’t killed or severely injured if a crash should happen.

To learn more about Vision Zero, visit the Harvard Public Health website.