The information is the same data transmitted to the Illinois Department of Transportation (IDOT) with two additions: the "Motivation for Stop", and the offense codes recorded....
Police incidents since 1988. Dates before that are incomplete - and could be data entry errors. Some addresses will not appear on maps because streets no longer exist or are not...
Arrests by the Urbana Police Department since 1988, with arrestee demographic data. Only the home city of the arrestee is available for mapping.
You can also access this registry using the API.