I'm not typically alarmist when I see stories claiming there's discrimination and racial profiling, but this one is more careful about it than most.
Often, studies talk about who gets stopped. My problem with those studies is that they can't or don't account for neighborhood or regional composition. For instance, why would it be significant that a high percentage of Hispanic people are stopped for traffic tickets in Chicago in an area that is largely comprised of Hispanic residents? None.
Contrast this with a recent study linked below that says something quite a bit more significant about traffic ticket enforcement in Illinois. This study is about what happened after the stop, and that's where the discrimination is suggested. To be fair, the Chicago Police Department comes off fairly well. The story is worth reading, and I welcome hearing your comments.
Study: Minorities more likely to get tickets, have vehicles searched - Chicago Sun-Times