Inside 100 million police traffic stops: New evidence of racial bias
Stanford University researchers have compiled the most comprehensive evidence to date suggesting there is a pattern of racial disparities in traffic stops. The researchers provided NBC News with the traffic-stop data — the largest such dataset ever collected — which points to pervasive inequality in how police decide to stop and search white and minority drivers.
Using information obtained through public record requests, the Stanford Open Policing Project examined almost 100 million traffic stops conducted from 2011 to 2017 across 21 state patrol agencies, including California, Illinois, New York and Texas, and 29 municipal police departments, including New Orleans, Philadelphia, San Francisco and St. Paul, Minnesota.
- Police stops: A "veil of darkness" test was done to analyze whether black drivers are being pulled over at a higher rate during the day than at night, when officers would have a harder time distinguishing race from a distance. After adjusting for the variation in sunset times across the year, researchers found a 5 to 10 percent drop in the share of stopped drivers after sunset who are black, suggesting black drivers are being racially profiled during the day.
- Police searches: Researchers reviewed the rate at which drivers were searched and the likelihood that those searches turned up illegal drugs and guns. There was evidence that the bar for searching black and Latino drivers is lower than that for white drivers, even though white drivers were more likely to have contraband. Across states, contraband was found in 36 percent of searches of white drivers, compared to 32 percent for black drivers and 26 percent for Latinos.
- Impact of marijuana legalization: After the legalization of recreational marijuana in Colorado and Washington state, there has been a reduction in searches of both white and minority drivers. But the search rate remains twice as high for minorities, a trend also noted in a 2017 Stanford study.