Twenty-two people were injured and one person was killed when a driver raced through a busy sidewalk in Times Square on Thursday. In the immediate aftermath, New Yorkers worried that the incident might have been a terrorist attack, akin to the fatal vehicle-ramming attacks in Stockholm in April or the mass-casualty attack in Nice in 2016. It wasn’t: A final determination on the crash has not been made, but the driver of the vehicle, Richard Rojas, may have been under the influence—a far more common threat on U.S. streets than terrorism.

The fatal tragedy might have been a lot deadlier were it not for the work of designers to boost public safety in Times Square over the last decade. The motorist drove north on the west-side sidewalk of Seventh Avenue for three blocks between 42nd Street and 45th Street, when he crashed into steel bollards—public-safety features introduced to Times Square in its recent reconstruction. “The car eventually impaled itself on the bollards,” says David Burney, former commissioner of New York City’s Department of Design and Construction. “If those bollards hadn’t been there, it would have been much worse.”

In fact, the death was the first pedestrian traffic fatality in Times Square since 2003. Burney, who is now the director of the Urban Placemaking and Management Program at the Pratt Institute, says that he regular takes his students through Times Square as a case study in how to do traffic calming. Between 2010 and 2017, the architecture firm Snøhetta rebuilt this area, one of the hottest pockets of foot traffic in the world. This redesign work, spread across two-and-a-half acres, included the dedication of a true public plaza for pedestrians in the heart of the Times Square Bowtie, the area between 42nd and 47th Streets along Seventh Avenue and Broadway. Pedestrian injuries in the Bowtie fell from an average of 62 injuries per year in 2006-2008 to 37 in 2014-2016—a 40 percent reduction, according to New York City’s Department of Transportation.

Before the redesign, pedestrians on wildly crowded sidewalks simply spilled into the streets as they neared the heart of Times Square. While security bollards are by no means everyone’s favorite urban landscape feature—you won’t see them in public plazas across Europe—they were a necessity for this tourist epicenter.

“That’s why there are bollards there—because of the concerns that Americans aren’t used to plazas,” says Faith Rose, former president of New York’s Public Design Commission and a partner at O’Neill Rose Architects.

Burney—who led his department’s work with New York City’s Department of Transportation, the Times Square Alliance, the New York Police Department, and other stakeholders—says that the bollards were added to the design on the recommendation of the NYPD. They’re K12-rated anti-ram steel security bollards, meaning they are meant to utterly withstand a collision from a vehicle traveling at 30 miles per hour.

While the cross-street bollards likely prevented more casualties today, rerouting traffic has led to the biggest boost in pedestrian safety. “Having two major north–south roads running through Times Square was a serious conflict between pedestrians and traffic,” Burney says. “Just closing Broadway, and liberating those five plazas from traffic for pedestrian use, was itself a major thing.”

The city’s Department of Transportation is working to extend pedestrian-safety features to intersections across the city. Times Square is the centerpiece of the New York City Plaza Program, through which DOT has funded the design and construction of dozens of new plazas, traffic-calming nodes, school-safety zones, and other urban-landscape improvements. At least seven pedestrian plaza projects are currently underway in Manhattan, Queens, and Brooklyn.

More traffic-calming measures are necessary, Burney says. Pedestrians still account for the majority of traffic fatalities in New York, per the city’s last pedestrian safety report. And as my colleague Laura Bliss explains, there’s more art than science in determining which design changes are specifically responsible for what effects when it comes to boosting pedestrian safety. This calculus gets even more difficult when drunk drivers are involved.

But one fix is known to be extremely effective: taking cars off the road.

“Personally I think what happened today strengthened the argument for further traffic closures for Times Square,” Burney says.