Illinois Vehicle Code book online.
All other motor vehicles shall exhibit at least 2 lighted head lamps, with at least one on each side of the front of the vehicle, which satisfy United States Department of Transportation requirements, showing white lights, including that emitted by high intensity discharge (HID) lamps, or lights of a yellow or amber tint, during the period from sunset to sunrise, at times when rain, snow, fog, or other atmospheric conditions require the use of windshield wipers, and at any other times when, due to insufficient light or unfavorable atmospheric conditions, persons and vehicles on the highway are not clearly discernible at a distance of 1000 feet.
In summary if a cop cant see you comming way down the road easily he will get you.
And just because. Rear lights must be seen from 500ft with parking lights on NOT brake lights.
