Louisiana Revised Statutes Tit. 32, § 351. Horns and warning devices

B. 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.

C. It is permissible but not required that any commercial vehicle 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.

D. 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 feet and of a type approved by the commissioner, but such siren shall not 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 events the driver of the vehicle shall sound the siren when reasonably necessary to warn pedestrians and other drivers of the approach thereof. However, motor vehicles which are owned and operated by members of nonprofit corporations as provided in R.S. 12:201 et seq. and which are tax exempt in accordance with Section 501(c) of the Internal Revenue Code, for exhibition in shows, parades, tours, and other special uses and not for general transportation may be equipped with a siren, whistle, or bell capable of emitting sound audible under normal conditions from a distance of up to five hundred feet but such sound equipment shall not be used except when such vehicle is participating in shows, parades, tours, and other special events.