Racial demographics explain the link between racial disparities in traffic stops and county-level racial attitudes

Disparities in the treatment of Black and White Americans in police stops are pernicious and widespread. We examine racial disparities in police traffic stops by leveraging data on traffic stops from hundreds of U.S. counties from the Stanford Open Policing Project and corresponding county-level data on implicit and explicit racial attitudes from the Project Implicit research website. We find that Black-White traffic stop disparities are associated with county-level implicit and explicit racial attitudes and that this association is attributable to racial demographics: counties with a higher proportion of White residents had larger racial disparities in police traffic stops. We also examined racial disparities in several post-stop outcomes (e.g., arrest rates) and found that they were not systematically related to racial attitudes, despite evidence of disparities. These findings indicate that racial disparities in counties’ traffic stops are reliably linked to counties’ racial attitudes and demographic compositions.