I don’t know DUI in Illinois, but maybe someone does know all the DUI case law so feel free to dispute this link.
This link is for Florida only, but I think it would work great in Illinois.
DUI check points are actually the police looking for expired registrations and stickers and all that, broken tail lights, arrest warrants, seized cars, etc. They are basically a revenue generator. But I have seen posts where a car’s plates or license was expired and the police left entire families out in the cold to walk home, whadda bunch of jerks.
They are best to avoid. Feel free to turn around and take an alternate route when you see one. And keep this flyer in the car. The lawyer is right, there are no officer friendlies, only a guy trying for a promotion or raise.