As part of the Iowa City Police Department’s ongoing efforts to ensure fair and equitable policing, the Department has partnered with Dr. Christopher Barnum since 2006 to collect demographic data on traffic stops. Barnum is an Associate Professor of Sociology and Criminal Justice at St. Ambrose University and director of the school’s Graduate Studies Masters in Criminal Justice program.

Barnum’s study evaluates two categories of discretionary police activity: the racial disparity of traffic stops to determine the likelihood of being stopped, and differences in the outcomes of traffic stops among racial demographics. The likelihood of being stopped is based on both roadside observations and census data.

Using data from 2019 and 2020 traffic stop behavior, Barnum’s most-recent study found steady or decreasing amounts of disproportionality in traffic stops. The study also found “comparatively low levels of disproportionality” in outcomes for citations. While higher levels of disproportionality were noted in arrest outcomes, Barnum’s study noted almost all arrests involved offenses in which the officer had “little or no choice in deciding to make an arrest.”

“Disproportionality continues to decline in the Iowa City Police Department, but the effort needs to continue,” said Chief Dustin Liston. “The ongoing work with Dr. Barnum has been critical to identifying potential issues and working on solutions. The police department maintains its commitment to fair and impartial policing by monitoring any possible disparities and addressing potential issues.”

2019/2020 Traffic study update


Watch the video below for a behind-the-scenes look at how the data is collected.


    City Government