In order to focus on metrics that are directly measurable—rather than guessing at demographics tracked using different systems and criteria—we compare the outcomes by race for people who have already been stopped. By choosing this focus, we do not mean to suggest that there are no racial disparities in who gets stopped. Agencies, especially those with high stop counts, should still consider their residential population when examining their data for bias.

Every traffic stop can produce several possible outcomes. For example, the officer may or may not search the driver. Officers may record different reasons to justify searches. They may receive consent from the driver to conduct a search, or they may establish probable cause, including through a dog sniff alert. During a search, the officer may or may not find contraband. The officer could also give a verbal warning, a written warning, or a citation.

We explore some of these outcomes below. Select an agency above and follow along.

Consent Searches

During a traffic stop, an officer may ask permission to search your car. If you agree, this is called a "consent search." Unlike other searches that require officers to identify some suspicion of a crime, the decision to conduct a consent search is left to the subjective judgment of the officer. Supervisors and courts do not review those decisions. These subjective, unreviewed decisions raise concerns about racial bias, whether conscious or unconscious.

Some argue that the rate at which drivers are searched (or asked to be searched) is not necessarily an indicator of discrimination because officers may base their decisions on evidence that the driver has contraband, and individuals in different racial groups may carry contraband at different rates. So let's compare the rates at which contraband was found (from now on referred to as "contraband hit rates") by Illinois law enforcement agencies during consent searches.

First, are minority drivers any more likely to be found with contraband? Darker bubbles represent agencies where the difference in hit rates are statistically significant. (Find an explanation of statistical significance and how we've chosen to display it here.) As you can see below, the minority contraband hit rates of most agencies do not significantly differ from white contraband hit rates.