Mississippi Code Title 63. Motor Vehicles & Traffic Regulations § 63-7-65

(1) 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 two hundred (200) feet. The driver of a motor vehicle shall, when reasonably necessary to ensure safe operation, give audible warning with his horn but shall not otherwise use such horn upon a highway. No horn or other warning device shall emit an unreasonably loud or harsh sound or a whistle.

(2) Any authorized emergency vehicle may be equipped with a siren, whistle, or bell, capable of emitting sound audible under normal conditions from a distance of not less than five hundred (500) feet and of a type approved by the department. No such siren shall be used except when such 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 said latter events the driver of such vehicle shall sound such siren when necessary to warn pedestrians and other drivers of the approach thereof.

(3) No vehicle shall be equipped with nor shall any person use upon a vehicle any siren, whistle, or bell, except as otherwise permitted in this section. No bicycle shall be equipped with nor shall any person use upon a bicycle any siren or whistle.

(4) Any vehicle may be equipped with a theft alarm signal device which is so arranged that it cannot be used by the driver as an ordinary warning signal.