The South Carolina police stop of Walter Scott on an ordinary road in a sprawling Southern city seems to fit a pattern identified by sociologists Charles Epp, Steven Maynard-Moody, and Donald Haider-Markel in a massive study of traffic stops in the Kansas City area, “Pulled Over: How Police Stops Define Race and Citizenship,” reports Slate. The authors identify two kinds of stops: traffic safety and investigatory. In the former, drivers are stopped for clearly breaking traffic laws. This is true for whites and blacks.
Where we see a racial difference is in investigatory stops. In these, drivers are stopped for exceedingly minor violations—driving too slowly, malfunctioning lights, failure to signal—which are used as pretext for investigations of the driver and the vehicle. Sanctioned by courts and institutionalized in most police departments, investigatory stops are aimed at “suspicious” drivers and meant to stop crime not traffic offenses. And as the authors note, “virtually all of the wide racial disparity in the likelihood of being stopped is concentrated in one category of stops: discretionary stops for minor violations of the law.” In the study, 60 percent of all stops for whites were for traffic safety, versus 35 percent for blacks. By contrast, 52 percent of all stops for blacks (versus 34 percent for whites) were for events in which the reasons were minor (“You didn't signal at the stop sign”). For 18 percent of black drivers, reasons for the stops were nonexistent, while only 8 percent of white drivers weren't given reasons for their stops.