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. Traffic stops appear since 2012, when the State revised the format to the current standard.
IMPORTANT!! (please click "More" to read this...) Adding the Offense Codes means that each line of information represents a single Offense.
For example: a traffic stop for speeding results in an arrest for an outstanding warrant and for possession of narcotics. That would appear on this listing THREE times (speeding, arrest warrant, and narcotics). The Incident Number will be the same (and the driver demographics), but the Crime Codes will be different on each line.
So counting rows of this dataset will return a higher count than the actual stops. This will cause some discrepancies with State data, which only count each stop once.
Please refer to the attachment for more details.