Study: Minority drivers in Iowa City stopped, searched, arrested at disproportionate rates
Researcher says not clear bias at play, however
IOWA CITY – Minority drivers were stopped at disproportionately higher rates by Iowa City police officers in recent years and were roughly three times more likely than other drivers to be searched and arrested, according to a study.
The researcher, however, told the City Council at a work session Monday night that he could not conclude racial bias was at play. And police Chief Sam Hargadine said while the results raise concerns, he believes his officers have no ill intentions and the release of the data will help his department “grow.”
“Our goal is to reduce disproportionate minority contact numbers,” he said.
The study follows increased discussion in recent years in Johnson County over what is commonly referred to as disproportionate minority contact in the criminal justice system, particularly for blacks and Hispanics.
Hargadine said that public debate led him to release the study results, which were initially intended to stay internal.
The study was done by Christopher Barnum, a St. Ambrose University sociology and criminal justice professor and a former Cedar Rapids police officer. Starting in 2006, he was given Iowa City police traffic stop data, and the study covers 2005-2007 and 2010-2012, with the middle two years unavailable.
Police officers were not told of the study so as to not affect their behavior, Hargadine said.
Barnum found that about 10 percent of drivers in Iowa City were minorities during the study period. Research has shown Asians are usually disproportionately underrepresented in traffic stops, so Barnum’s study groups them with whites.
From 2005 through 2007, about 14 percent of traffic stops involved minority drivers, which the study says is a “comparatively low” level of disproportionately.
From 2010 through 2012, however, that number increased to 18 to 19 percent.
Barnum and Hargadine noted that the escalation occurred as the Police Department increased patrols in southeast Iowa City following concerns of violence in the area. Minorities make up a bigger percentage of the population in southeast Iowa City than other parts of town, according to census data.
The increased disproportionality in traffic stops appears to be driven by increased police activity in southeast Iowa City, Barnum told the council.
The study also found that minority drivers were 2.8 times more likely to be arrested on a traffic stop and 3.45 times more likely to be asked by an officer to have their vehicles searched than other drivers even though officers were more likely to seize items from white and Asian drivers.
Barnum said this data is a good place to look for bias, but he said he could not do that with Iowa City because officers did not always properly record when a search resulted from a request versus when officers had probable cause and did not need the driver’s consent.
Council member Kingsley Botchway II said, based on concerns expressed by community members, he’d like more study on whether bias is at play.
“You’re saying disproportionality exists, except you’re not sure what you can attribute it to,” he said.
The council agreed to continue the study for at least a couple of more years and to further analyze the existing data.
Barnum said he’s found in other communities that officers change their behavior when they know they’re being watched.
“I think there’s a good chance the numbers will change, ... but that’s not to say there’s a problem now,” he said.
A 2002 study by the University of Louisville determined racial profiling of drivers by police officers was not a problem in Iowa City. Two University of Iowa professors criticized the study’s methodology at the time.