Code of Alabama
Division 1 - General Provisions.
Section 32-5-213 - Horns and Warning Devices.

(a) Every motor vehicle when operated upon a highway shall be equipped with a horn in good working order capable of emitting a sound audible under normal conditions for a distance of not less than 200 feet.
It shall be unlawful for any vehicle to be equipped with or for any person to use upon a vehicle any siren or for any person at any time to use a horn otherwise than as a reasonable warning or to make any unnecessary or unreasonably loud or harsh sound by means of a horn or other warning device.
(b) Every police and fire department and fire patrol vehicle and every ambulance used for emergency calls shall be equipped with a siren, bell, ululating multi-toned horns or other electronic siren type device approved by the Director of Public Safety.
(c) Any person violating any of the provisions of this section shall be guilty of a misdemeanor.