625 ILCS 5/12-211: Number of driving lamps required or permitted.

(a) At all times specified in Section 12-201, at least 2 lighted driving lamps shall be displayed, one on each side of the front of every motor vehicle other than a motorcycle, except when such vehicle is parked subject to the regulations governing lights on parked vehicles.

(b) Whenever a motor vehicle equipped with driving lamps as herein required is also equipped with any auxiliary driving lamps or a spot lamp or any other lamp on the front thereof, not more than a total of 4 of any such lamps on the front of a vehicle shall be lighted at any one time when upon a highway.