Tap any paragraph to write a margin note. Your notes collect in the Desk below the text and file under cases with @. The side-by-side margin rail opens on a larger screen.

§
Marginalia
Code · Arizona · Title 28 — Motor Vehicles

28-954. Horns and warning devices

358 words·~2 min read·/az/title-28/28-954

A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

A. A motor vehicle when operated on a highway shall be equipped with a horn that is in good working order and that is capable of emitting sound audible under normal conditions from a distance of at least two hundred feet. Any horn or other warning device shall not emit an unreasonably loud or harsh sound or a whistle.
B. If reasonably necessary to ensure the safe operation of a motor vehicle, the driver shall give an audible warning with the driver's horn but shall not otherwise use the horn when on a highway.
C. A vehicle shall not be equipped with and a person shall not use on a vehicle a siren, whistle or bell, except as otherwise permitted in this section.
D. A vehicle may but is not required to be equipped with a theft alarm signal device that is arranged so that it cannot be used by the driver as an ordinary warning signal.
E. An authorized emergency vehicle may be equipped with a siren, whistle or bell that is capable of emitting sound audible under normal conditions from a distance of at least five hundred feet and that is of a type approved by the department. The siren shall not be 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 or when necessary to serve a civil traffic complaint. During these events the driver of the vehicle shall sound the siren when reasonably necessary to warn pedestrians and other drivers of the approach of the emergency vehicle.
F. A siren shall be allowed on a fire engine that is solely used for hobby or display purposes and that has been issued a historic vehicle license plate pursuant to section 28-2484 if either of the following applies:
1. The siren is covered and is not activated while a person is transporting or driving the vehicle to or from a parade, authorized assemblage of historic vehicles or test.
2. The siren is activated only in a parade, for an authorized assemblage of historic vehicles or for testing purposes.
★   the supreme law of the land   ★
Don't Tread on Me
E Pluribus Unum — out of many, one

"If you don't know your rights, you don't have any."

Marginalia · a citizen's law index
A research desk, not legal advice. Always read the cited source before relying on a summary.
Questions or an issue? support@self-law.org
disclaimerMarginalia is a research index, not a law firm. Nothing on this site is legal, tax, or financial advice and no attorney–client relationship is formed by using it. Statutes, regulations, and case law change; summaries, search results, AI output, and member posts may be incomplete, out of date, or wrong. Any interpretation drawn from material on this site should be validated by a licensed attorney in your jurisdiction before you act on it.