Jan. 26 2016

Google Street View Could Save Your Life

Mailman School researchers take us on a virtual tour of some of New York City’s most dangerous intersections

Pedestrian traffic fatalities in New York City are at their lowest rate since 1910 when the city started keeping reliable statistics. All told, 134 pedestrians were killed in 2015, down from 139 the prior year. As Mayor Bill de Blasio’s Vision Zero program looks for new avenues to eliminate these deaths altogether, Mailman School research may provide important guidance. In a new study, researchers used Google Street View to assess more than 500 street crossings to find out what makes them safe or dangerous for pedestrians.  

Transmission got in touch with the study’s first author, Stephen Mooney, a doctoral student in Epidemiology, to arrange a virtual tour of five intersections in order to glean lessons on how to keep our time on and off the sidewalk accident-free. More than individual safety tips, the research method could give officials an efficient way to plan improvements that make the city safe for everyone. In fact, Mooney and Andrew Rundle, associate professor of Epidemiology and the study’s senior author, are already in touch with Vision Zero with an offer to help. “To understand what to change and where to change it, we need to know more about what is and isn’t already working to make our streets safe,” says Mooney. 

1. Safety in Numbers: Eighth Avenue and 40th Street.

Not surprisingly, the bulk of pedestrian injuries happen where there are a lot of pedestrians: in particular, Midtown Manhattan, as this heatmap makes clear. But the team’s analysis of five years of injury-causing collisions showed that intersections with more foot traffic had lower risk of injury per pedestrian by as much as 40 percent. “We found, consistent with other literature, that pedestrian density makes things safer on a per-pedestrian basis,” says Mooney.

2. Crosswalks Are Not an Invisible Barrier: MacDougal and West 8th Street.

Focusing on Midtown and other high-risk areas is a good way to reduce the public health burden of pedestrian injury, according to Mooney. But when you’re interested in studying how the built environment makes intersections more or less safe, it is important to account for differences in pedestrian populations. In that light, it would be a mistake to make Midtown look more like the outer boroughs.

This Greenwich Village intersection sees 0.3 collisions a month involving pedestrians, a small number for its large pedestrian population. There are few visual distractions, the road is narrow, and there are no marked crosswalks across West 8th. Surprisingly, the researchers found crosswalks and pedestrian signals did not make for safer streets. In fact, intersections with crosswalks and pedestrian signals had more injuries, all else being equal. According to Mooney, one possible explanation is that city puts these safety features in places where they’re most needed: across big streets with a lot of traffic. 

3. Don’t Run for That Bus: Avenue K and Ralph Avenue.

By contrast, this Brooklyn intersection sees about 1.4 collisions per month involving pedestrians, in spite of almost certainly having a lower pedestrian population than MacDougal and West 8th. While there are marked crosswalks, the markings are wearing off. Another factor could be the presence of a bus stop, which the researchers found could increase risk by 120 percent. “The bus stop could be a distraction for drivers crossing the intersection, and might also cause pedestrians to make risky crossings in order to catch buses,” says Mooney.

4. Killer Ads: Sixth Avenue and Watts.

This SoHo crossing has a high collision rate (2.1 per month) for its pedestrian population. The large billboard advertising on both sides of the street may distract drivers and pedestrians. In fact, the researchers showed that, overall, intersections with billboards had 42 percent more injuries.

5. Danger Zones: 63rd Road & Queens Boulevard.

In the five years the researchers studied, a lot of intersections, particularly in the outer boroughs where foot traffic is more rare, had no pedestrian injuries at all. This wasn’t the case everywhere in the outer boroughs, though. The city has known for years that Queens Boulevard, aka, “the Boulevard of Death,” is extremely dangerous, with about two collisions per month at this intersection alone. “Pedestrian signals and crosswalks don’t making crossing 10 lanes of traffic totally safe,” says Mooney. Future studies using Street View could assess to what extent traffic-calming features like speed bumps and curb bulbs help.

The latest traffic safety numbers are great news, says Mooney. “I think Street View can help bring the number of accidents down more, particularly by helping to figure out what we should be doing where.”