Public Release: 

NYC pedestrian traffic makes for safer street crossings: Google Street View study

Google Street View provides accurate and quick assessments of pedestrian safety, shows billboards are dangerous

Columbia University's Mailman School of Public Health

Researchers at Columbia University's Mailman School of Public Health have developed a novel method to assess how the streetscape affects the chances pedestrians will be injured by drivers. Using Google Street View the researchers assessed the pedestrian environment at more than 500 New York City street intersections. Findings show that using Google's images instead of visiting collision sites in person resulted in substantial efficiency gains in conducting research on pedestrian safety. The study is published online in the American Journal of Public Health.

"Using Google Street View to assess intersection characteristics works as well as, if not better than visiting sites in person, at much lower cost and with fewer logistical headaches," said Stephen Mooney, a graduate student in Epidemiology and co-author. Comparing environment characteristics to the frequency of injury-causing collisions captured by Google Street View over five years showed that intersections with more pedestrians had lower risk of injury per pedestrian. The researchers also found that more injuries occurred in contexts with visual distractions such as billboards and bus stops.

"The Google Street View approach to conduct 'virtual' neighborhood inspections does away with the need for field teams to conduct in-person audits," said Andrew Rundle, DrPH, associate professor of Epidemiology, who led the research team. "To our knowledge, virtual audits have not previously been used to assess risk factors for pedestrian injury."

An earlier in-person assessment of 850 intersections in California and Washington State required site visits that would have taken one person three years to complete. Rundle and Mooney estimate their method would have taken one person about a month to complete data collection for the same 850 intersections.

Consistent with prior research incorporating site visits, the new study found that, compared to other intersections, injury incidence per pedestrian was lower at intersections with heavy pedestrian traffic. Marked crosswalks (80-percent increase), pedestrian signals (156-percent increase), bus stops (120-percent increase), and billboards (42 percent increase) were associated with increased risk. "Our finding that marked crosswalks are associated with elevated risk is concordant with previous findings, though the reasons for this somewhat counterintuitive association are not well established. " said Mooney.

The researchers point out that investments in pedestrian safety infrastructure, such as improving lighting, adding speed bumps, or maintaining pavement markings can substantially improve pedestrian safety and may be a particularly cost-effective way to improve population health. Recently, several major cities, including New York City, have developed high-profile plans to improve pedestrian safety city-wide. New York alone has installed 1,500 pedestrian signals and re-engineered dozens of roads and intersections.

"The large burden of injury coupled with the sparse empirical literature justifies more research into risk factors for pedestrian injury and into the effectiveness of interventions," noted Rundle. "We are looking to undertake additional research applying this virtual neighborhood inspection methodology to study pedestrian injury risk in other cities. "

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The study was funded by NIH NICHD(R21HD062965), CDC (1 R49 CE002096), and NCI training grant T32-CA09529).

About Columbia University's Mailman School of Public Health

Founded in 1922, Columbia University's Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master's and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including ICAP (formerly the International Center for AIDS Care and Treatment Programs) and the Center for Infection and Immunity. For more information, please visit http://www.mailman.columbia.edu

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