Utah's Auxiliary Light Rule: White or Amber Front, Amber Side, Steady, No Brighter Than Stock

Before 2024 a Utah driver with a light bar or rock lights had to work the answer out of the general lamp sections. Chapter 118 of the 2024 General Session added Subsections (7), (8) and (9) to Section 41-6a-1604, effective 1 May 2024, and they now state the rule directly. The operative trigger is illumination on a public roadway, not installation. An auxiliary light may be fitted and left dark off-road or in a driveway; Subsection (7) bites when it is switched on where the public drives.

Four conditions apply at once, and all four must be met. On colour and position, Subsection (7)(a) requires white or amber for a light on or visible from the front, amber for a light on or visible from the side, and amber or red for a light on or visible from the rear. That kills the common under-glow and accent colours, and note the test is what the light is visible from, not merely where it is bolted. On behaviour, Subsection (7)(b) requires a steady beam that does not blink, oscillate, rotate or flash. On intensity, Subsection (7)(c) sets the vehicle's own original equipment lighting as the ceiling: the auxiliary beam may not be brighter, may not have greater candlepower, and may not distract from the visibility of the factory lighting. And Subsection (7)(d) adds a general prohibition on distracting or impairing the vision of the operator or other drivers.

Two carve-outs sit in Subsection (8). Lighting installed by the vehicle's manufacturer in accordance with 49 C.F.R. Sec. 571.108, the federal lamps and reflective devices standard, is outside the rule. So are devices provided by transportation network companies, as defined in Utah Code Section 13-51-102, to identify and indicate the status of a vehicle used to provide transportation network services, but only when approved by the department as permitted by Section 41-6a-1602. That is the Utah statutory basis for the illuminated rideshare beacon on a windshield. Subsection (9) exempts an off-highway vehicle operating on a public road designated for off-highway vehicle use.

Section 41-6a-1604 does not stand alone. Section 41-6a-1616(1)(c) caps the front of a vehicle at a total of four lighted lamps that project a beam of an intensity greater than 300 candlepower, counting head lamps, auxiliary lamps, spot lamps and any other such lamp together, so a driver who adds a pair of high-output pods to two headlights has reached the limit. Section 41-6a-1616(1)(a) requires any lamp projecting more than 300 candlepower to be aimed so that no part of the high intensity portion of the beam strikes the roadway more than 75 feet ahead, though Subsection (1)(b) excepts head lamps, spot lamps, auxiliary lamps, flashing turn signals, hazard warning lamps, school bus warning lamps and snow plows operated at the direction of the state or a political subdivision.

Colour restrictions at the front are absolute in two directions. Section 41-6a-1616(2)(a) bars any vehicle on a highway from carrying a lamp or device capable of displaying a red light visible from directly in front of the centre of the vehicle, except an authorised emergency vehicle, a school bus under Section 41-6a-1302, or a simulated emergency vehicle used under Section 41-6a-1718. Subsection (2)(b) does the same for blue, with the exception narrowed to a law enforcement vehicle or a simulated emergency vehicle. Section 41-6a-1616(3) then lists the only lawful uses of flashing lights, including bicycle taillights, authorised emergency vehicles, turn signals, hazard warning lights, school bus lights, highway construction and maintenance vehicles under Section 41-6a-1617, simulated emergency vehicles, and the continuously flashing supplemental stop lamp system defined in Section 41-6a-1604(6). Subsection (4) bars a rotating light on any vehicle except an authorised emergency vehicle or a media production vehicle used under Section 41-6a-1718.

Spot lamps get their own section. Section 41-6a-1610(1) allows no more than two, and Subsection (2) forbids aiming or using a lighted spot lamp so that any part of the high intensity portion of the beam strikes the windshield, windows, mirror or occupant of another vehicle in use. Back-up lamps under Section 41-6a-1612(1) must emit white light and may not be lit while the vehicle is moving forward.

Equipment approval runs through Section 41-6a-1618, which bars using, selling or offering for sale any head lamp, auxiliary fog lamp, rear lamp, signal lamp, required reflector or part that tends to change the original design or performance unless it complies with the specifications adopted under Section 41-6a-1601. Section 41-6a-1601(2)(c)(iv) adopts 49 C.F.R. 571 Standard 108 for lights and illuminating devices, and Section 41-6a-1601(3)(b) preserves the use of additional parts and accessories not inconsistent with the chapter or the department's rules.

A violation of Section 41-6a-1604 is an infraction under Subsection (10), and violations of Sections 41-6a-1610, 41-6a-1616 and 41-6a-1618 are infractions under their own final subsections. Section 76-3-301(1)(e) caps an infraction fine at $750 before surcharges. Section 41-6a-1601(1)(a) supplies the parallel offense for the owner: a person may not operate, and an owner may not cause or knowingly permit to be operated, a vehicle that is equipped in any manner in violation of the chapter, which reaches the person who fitted the lights as well as whoever is driving.

Section 41-6a-1618(1) reaches the seller and installer of non-conforming lamps. A driver who needs to run equipment outside the specifications can apply under Section 41-6a-1602 for a permit to operate a vehicle in violation of the equipment regulations, and that is the same mechanism Section 41-6a-1604(8)(b) uses to approve transportation network company status devices. Because Utah requires a safety inspection only for the vehicle categories listed in Section 53-8-205, lighting compliance on an ordinary passenger vehicle is enforced at the roadside rather than in an inspection lane.