Racial Bias in Traffic Stops: Tests of a Unified Model of Stops and Searches

This paper develops a model of traffic stops and subsequent searches in which police officers use information about the race of drivers to maximize a well defined objective. The model provides a behavioral foundation absent from Grogger and Ridgeway’s (2006) elegantly simple test and, by incorporating searches, adds two complementary tests. Using data collected during 2002 by the Minneapolis Police Department, the tests rule out (1) statistical discrimination, (2) taste-based discrimination by optimizing police officers, and (3) statistical discrimination with cognitive limitations. The pattern of results is consistent with implicit discrimination.