How Departments Compare
Traffic stops, one year at a time.
Pick a year to see every department's rate ratio vs. White for Black and Hispanic drivers combined, from the highest to the lowest. The numbers come with a lot of caveats, so please read them first.
Before you read the table
- What the ratio is. Black and Hispanic drivers together are stopped at some rate relative to their share of the benchmark population, and White drivers at another. The ratio divides one by the other: 2.0 means twice the White rate, and 1.0 means the same.
- A high ratio is not proof of bias. The typical department has a ratio above 1.0. Who lives in an area, who drives through it and how the population is counted all move the number.
- Compare like with like. Campus police, sheriffs and highway towns have very different traffic from a city police department, so filter by type. Recent years use different benchmark methods (crash-based or distance-based), which can't be compared directly, so filter by method too.
- Few stops, shaky numbers. A department needs a minimum number of stops in each group to appear. The low end is what the ratio would be if both groups sat at the bottom of IDOT's 95% range. Sorting by it puts the more certain results first.
- Black and Hispanic combined leaves out Asian and Native American drivers and can hide groups that move in opposite directions, so each group is shown separately as well.
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| # | Department | Black + Hispanic vs. White |
Low end | Black vs. White |
Hispanic vs. White |
Stops White / Black + Hispanic |
Benchmark |
|---|
Black and Hispanic ranges are IDOT's own 95% intervals, which include uncertainty in the population benchmark. The combined ratio and its low end are worked out from the same published numbers.