If you've ever wondered about policing patterns in your community, you can use this app as a reference.

Traffic stops, the most common interaction between police and the public, have been a matter of public record in Illinois since 2004, when a state law began requiring police to log key details every time they pull over a car: the race of the driver, the reason for the stop, the outcome and many other points of info.

Twenty years and 40 million-plus stops later, WBEZ and the Investigative Project on Race and Equity have assembled a comprehensive database of traffic stop records spanning two decades and more than 1,000 law enforcement agencies across Illinois. Our reporting has revealed increasing racial disparities, declining police compliance and limited oversight from the state.

Matt Kiefer and Andjela Padejski are data journalists with WBEZ.

Claire Kurgan and Zahid Khalil contributed to this interactive.