Every motor vehicle when operated upon a highway shall be equipped with a horn in good working order and capable of emitting sound audible under normal conditions from a distance of not less than 200 feet, but no horn or other audible device shall emit an unreasonably loud or harsh sound or a whistle or unnecessary noise. The driver of a motor vehicle shall when reasonably necessary to ensure safe operation give audible warning with his or her horn but shall not otherwise use the horn when upon a highway.
Statutory reference:
Similar provisions, see ILCS Ch. 625, Act 5, § 12-601