An independent review of traffic stops in 2018-2019 initiated by the Ames Police Department found negligible evidence of racial bias by Ames police officers. The study was requested as a proactive step to evaluate whether racial disparities existed in traffic stops and the outcomes. Both the Ames Police Department and Iowa State University Department of Public Safety participated in the study.

The review, conducted by Chris Barnum with CR Research Group LC, examined the number of traffic stops by area, the time of day, and the outcomes – citations, warnings, and arrests. These data points were used to assess disproportionality of drivers based on their race. As noted in the report, disproportionality can indicate bias or discrimination, but it may also reflect differences in driving behavior, vehicle condition or driver-license status. The study did not control for other factors that may influence traffic stops and outcomes.

According to the report, there is little evidence that officers stopped a greater proportion of people of color compared to white drivers. The disproportionality index (the measurement used to assess racial disparity) for both departments was almost always lower than .05, which is described in the report as a low confidence indicator of disproportionality.

The review allows the departments to evaluate performance over time and is part of the ongoing efforts to strengthen relationships with the community. The Ames Police Department will continue to provide bias-based police training for officers, share reports on police activity, and pursue opportunities to engage the community in conversations about race. Learn more:

Watch the Presentation of the Traffic Stop Study Report

Ames Police Department Traffic Stop Study Report

Ames Traffic Stop Study Presentation Slides