Arizona Auxiliary, Fog and Driving Lamp Rules

The permission itself is A.R.S. section 28-938, and it is written as a closed list of four items with numbers attached to each. One spot lamp is allowed, and when it is lit and the driver is approaching another vehicle it must be aimed so that no part of the high intensity portion of the beam goes to the left of the prolongation of the extreme left side of the vehicle, or more than one hundred feet ahead. Two fog lamps are allowed, mounted on the front between twelve and thirty inches above the surface the vehicle stands on, and aimed so that with the vehicle unloaded no part of the high intensity portion of the light left of the vehicle center projects, twenty-five feet ahead, higher than four inches below the center of the lamp. Two auxiliary passing lamps are allowed between twenty-four and forty-two inches, and two auxiliary driving lamps between sixteen and forty-two inches, both categories being additionally required to meet everything in sections 28-921 through 28-949.

That forty-two inch ceiling is the number that decides most modern light bar questions in Arizona. A bar mounted on the roof or on the top of a windshield frame sits well above forty-two inches, so it does not fit paragraph 3 or paragraph 4 of section 28-938 and is not among the additional equipment the article permits. Section 28-921(B) does say the equipment article does not prohibit additional parts and accessories, but only where the use is not inconsistent with the article, and a forward-facing lamp mounted outside the stated band is inconsistent with it.

A second cap runs across all of them. Under section 28-946(B), where a motor vehicle already carries the head lamps the article requires and also carries auxiliary lamps, a spot lamp or any other front lamp projecting a beam of intensity greater than three hundred candlepower, not more than four of those lamps may be lighted at any one time when the vehicle is on a highway. Head lamps count toward that four. Section 28-947(A) then adds an aiming rule for lamps that are not head lamps, spot lamps, auxiliary lamps or flashing front direction signals: any such lamp above three hundred candlepower must be directed so that no part of the beam strikes the roadway more than seventy-five feet from the vehicle. Auxiliary lamps are excluded from that particular sentence, which is why the height bands and the four-lamp cap do the real work on an Arizona build.

Color is handled in two places and it is strict. Section 28-947(B) bars driving or moving a vehicle on a highway with any lamp or device capable of displaying a red, or red and blue, light or lens visible from directly in front of the center of the vehicle, and states flatly that lights visible from the front shall be amber or white. Two exceptions exist. The first covers authorized emergency vehicles and an off-duty law enforcement officer using red or red and blue for traffic control while employed by an entity other than the officer's agency. The second covers an emergency vehicle kept solely for hobby or display that carries a historic vehicle license plate issued under section 28-2484, provided the lights are covered and not activated while the vehicle is driven to or from a parade, authorized assemblage of historic vehicles or test, or are activated only at the parade, assemblage or test itself. From the rear, section 28-931(C) requires all lighting devices and reflectors mounted on the rear to display or reflect red, excepting only the stop or signal lamp, which may be red, amber or yellow but must be red on a commercial vehicle as defined in section 28-2231, and the license plate lamp and backup lamp, which are white. Underglow is decided by those two sentences rather than by any dedicated statute: amber or white forward, red rearward, and nothing that can show red or blue to oncoming traffic.

Flashing is separately prohibited. Section 28-947(C) permits flashing lights on motor vehicles only on authorized emergency vehicles, school buses and snow removal equipment, as warning lights on disabled or parked vehicles, and as turn indicators. Subsection D then carves out a hazard-warning system: a vehicle may carry lamps warning other drivers of a traffic hazard requiring unusual care, mounted at the same level and as widely spaced laterally as practicable, showing simultaneously flashing white or amber to the front and simultaneously flashing amber or red to the rear, or any shade between those pairs, and visible at not less than one thousand five hundred feet at night in normal atmospheric conditions. Subsection E gives motorcyclists a headlamp modulator: the beam may be modulated between higher and lower brightness at two hundred to two hundred eighty cycles per minute, but not during the hours of darkness defined in section 28-922.

Smaller decorative and utility lamps sit in section 28-940. A motor vehicle may carry not more than two side cowl or fender lamps emitting amber or white light without glare, not more than one running board courtesy lamp on each side emitting white or amber without glare, and not more than two backup lamps, which may not be lit while the vehicle is moving forward. Section 28-949 closes the loop on hardware: a head lamp, auxiliary driving lamp, rear lamp, signal lamp, required reflector or any part of one that tends to change the original design or performance may not be sold or used unless it is of a type meeting applicable federal safety standards, it must bear the trademark or name under which it was approved so as to be legible when installed, and it must be mounted and aimed to focus per those federal standards.

Section 28-921(A) reaches both the driver and the owner: a person may not drive, and an owner may not knowingly cause or permit to be driven, a vehicle that lacks required lamps in proper condition and adjustment or that is equipped in any manner in violation of the equipment article. Because these sections sit in Title 28, chapter 3, section 28-121(B) makes a breach a civil traffic violation rather than a misdemeanor, and section 28-1598 caps the civil penalty at two hundred fifty dollars plus the surcharges the court must levy under sections 12-116.01 and 12-116.02.

In practice enforcement runs through section 28-982. The superintendent of the highway patrol, designated Department of Public Safety officers and any peace officer may require a driver to stop and submit the vehicle to inspection wherever there is reasonable cause to believe it is not equipped as required by law. If a lamp is wrong, the officer issues a written notice that specifies the particulars and states that a certificate of correction or adjustment of illegal or faulty equipment must be obtained within five days. Removing or relocating the offending lamp inside that window is the intended outcome. Arizona has no annual safety inspection to catch a non-compliant lamp beforehand, so a light bar installed on a Saturday is only ever tested by a traffic stop.