Okla. Stat. tit. 47, § 47-12-401: Horns and warning devices

A. 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, but no horn or other warning device

shall emit an unreasonably loud or harsh sound. The driver of a

motor vehicle shall, when reasonably necessary to ensure safe

operation, give audible warning with a horn but shall not otherwise

use such horn when upon a highway. No driver of any vehicle shall

use a horn when passing a person riding a bicycle, equine or animal-

drawn vehicle under normal conditions if no imminent danger of a

collision exists.

B. No vehicle shall be equipped with nor shall any person use

upon a vehicle any siren, except as otherwise permitted in

subsection D of this section.

C. 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. A theft alarm signal device shall not use

a siren, as described in subsection D of this section.

D. Every authorized emergency vehicle shall, in addition to any

other equipment and distinctive markings required by this title, be

equipped with a siren, or similar device, 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 of

Public Safety, 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 said latter events the driver of such vehicle shall sound said

siren when reasonably necessary to warn pedestrians and other

drivers of the approach thereof.

E. It shall be unlawful for any person to use a device capable

of producing auditory warning signals similar to that on an

authorized emergency vehicle or to use audible signal equipment from

a motor vehicle for the purpose of causing any other motor vehicle

operator to yield right-of-way and stop, or which actually causes

any other motor vehicle operator to yield the right-of-way and stop,

whether intended or not. The provisions of this subsection shall

not apply to the operators of authorized emergency vehicles.