Being a pedestrian in the United States is much more dangerous for black, Native American and Hispanic people than for whites.
Blacks make up 12.2 percent of the population but accounted for 19.3 percent of all pedestrian deaths in the decade ending in 2014, according to a Smart Growth America study. The situation is even worse for Native Americans, who have 4.5 times the pedestrian fatality rate as whites. Hispanics, meanwhile, make up 16.9 percent of the population but 21.5 percent of these deaths. In fact, the study found that the fatality rates of non-white pedestrians exceeded their share of the population in at least 42 states and the District of Columbia.
It's not clear why those disparities are so stark, but there are many plausible explanations.
Governing, for example, showed in 2014 that poorer neighborhoods, which tend to have more minorities, have disproportionately higher rates of pedestrian deaths. This could be because low-income neighborhoods tend to have lower-quality infrastructure; they may lack sidewalks, adequate lighting and sufficient road crossings for pedestrians.
Academics have also looked at how differences in the socioeconomic status, urban environment or alcohol use of different demographic groups might lead to disparities in pedestrian fatality rates.
But two recent studies -- one out of Portland, Ore., and the other out of Las Vegas -- raise another possibility: Drivers treat pedestrians near the roadway differently depending on their race.
In the Las Vegas experiment, researchers studied what happened when a white woman and a black woman of similar height and build in neutral clothing tried crossing roads at marked intersections in two different neighborhoods, one high-income and the other low-income.
(There were differences in the design of the roads, too. The crosswalk in the high-income area crossed six lanes in a stretch where the speed limit was 45 mph; the street in the low-income neighborhood had four lanes and a speed limit of 35 mph.)
The most alarming finding for the researchers was that, when the women were in the middle of the road, cars in the high-income area with the faster, wider road were seven times less likely to yield to the black pedestrian than the white pedestrian.
But when the women were waiting on the sidewalk for cars to slow down, drivers in the higher-income area were actually slightly more likely to stop for the black pedestrian than the white one.
In general, motorists in the lower-income neighborhood were more accommodating than drivers in the wealthier area. Regardless of race, the car closest to the sidewalk stopped to let the walker proceed 70 percent of the time in the low-income area, compared to just 52 percent of the time in the high-income neighborhood. (The drivers in the lower-income neighborhood with the slower street showed no significant difference in how they responded to the different pedestrians.)
Courtney Coughenour, a public health professor at the University of Nevada Las Vegas (UNLV) who led the study, says other experiments, including follow-up studies she has been involved in, have found similar disparities in motorists' reactions.
In fact, one of the reasons Coughenour’s team conducted the experiment was to see whether the same type of disparate treatment of pedestrians occurred in the sprawling neighborhoods of Las Vegas as earlier researchers had found in a much more dense environment in Portland.
In the 2013 Portland study, researchers kept track of how long it took drivers to yield to black and white men at the side of the road. About half of the cars that first encountered the pedestrians stopped to let them pass. But there was a big difference in what happened when the first car kept going.
In those situations, blacks were twice as likely to have to wait for two or more cars to pass before they could go. That meant it took those pedestrians twice as long to cross the street.
Tara Goddard, a researcher at Portland State University who led the field study, says the results are particularly significant in light of other research that shows similar biases in other fields.
"There is evidence of biases affecting policing, doctor-patient interactions and hiring," she notes. It would be illogical, she says, to presume that those prejudices wouldn't carry over to drivers. “That’s not how human behavior works.”
In fact, driver behavior around pedestrians varies not just by who the pedestrians are but also by who the drivers are. One well-publicized 2012 study from the University of California, for example, found that people who drive more expensive vehicles are less likely to slow down to let walkers cross.
For Goddard, the lesson is that road engineers need to minimize the potential impact of those built-in biases by drivers.
“As a planner and an engineer, it is very difficult to change these larger, cultural issues of biases. What we can affect -- and what has very real benefits -- is changing the roadway environment,” she says.
Traffic engineers can design roadways that give pedestrians more visibility and more space, says Goddard. Adding crosswalks and other traffic devices for pedestrians helps drivers better understand that pedestrians are intended users of the road.
Roadway designers can also slow down traffic, which "allows us to better use our executive function” instead of making snap decisions, says Goddard. That’s important because our minds often take shortcuts while performing a complex task like driving, and those shortcuts often reflect implicit biases that a driver is not even conscious about.
Coughenour, the UNLV professor, says the studies’ results could also influence public education campaigns. That’s an issue that strikes close to home for her: Nevada officials declared an epidemic of pedestrian deaths in the state last March, and one of the things they’ve done as a response is step up public awareness campaigns.
“It’s important to educate the pedestrian because even though they might have the right of way, they are the more vulnerable user,” she says. “It’s really important that we continue driver education and pedestrian education. But I do hate it. I hate that we put the onus on the pedestrian.”