Discrimination During Traffic Stops: How an Economic Account Justifying Racial Profiling Falls Short

The last decade has seen a noted increase in the amount of traffic-stop data available for researchers hoping to analyze racial profiling on America’s highways. A group of economic scholars—Knowles, Todd, and Persico—proposed a bright-line statistical test that asks whether different racial groups have the same hit rate, or to put it differently, are searches of individuals equally efficacious, regardless of their race? Accepting this conception of racial profiling as a minimum floor, I apply the test to a superior and newly-compiled data set of nine million Illinois traffic stops. The Illinois police fail the bright-line test and show signs of discrimination against Hispanic, Asian, and Black motorists. I then examine whether Seventh Circuit equal protection precedent would permit an Equal Protection claim based on that statistical disparity alone, concluding that additional evidence is needed to satisfy the discriminatory intent prong.