Rules for horns and warning devices on vehicles

(a) Every motor vehicle when operated upon a highway must 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 a horn or other warning device may not emit an unreasonably loud or harsh sound or a whistle. The driver of a motor vehicle shall, when reasonably necessary to ensure safe operation, give audible warning with the driver’s horn; but may not otherwise use such horn when upon a highway. (b) A vehicle may not be equipped with nor may any person use upon a vehicle any siren, whistle, or bell, except as otherwise permitted herein. (c) Any authorized emergency vehicle may be equipped with a siren, whistle, bell, or air horn capable of emitting sound audible, under normal conditions, from a distance of not less than 500 feet, and of a type approved by the director of budget and fiscal services; provided that the use of the air horn is restricted to heavy fire equipment such as fire engines, ladder trucks, and rescue trucks; and provided further, that the siren or air horn is not used except when the vehicle is operated in response to an emergency call or in the immediate pursuit of an actual or suspected violator of the law, in which latter events the driver of the vehicle shall sound the siren or air horn when necessary to warn pedestrians and other drivers of the approach thereof. (d) Any truck used to haul dirt, rock concrete, or other construction material may be equipped with a horn, bell, or whistle in the rear thereof, capable of emitting a sound audible under normal conditions from a distance of not less than 200 feet; such warning device, however, to be sounded only while the truck is backing up. )