Tennessee Auxiliary Lights: Two Extra Lamps, White or Amber Only

The counting rule comes first. Under § 55-9-402(a)(1) a car must carry at least two and not more than four headlights, one on each side of the front. Subdivision (a)(2) then permits auxiliary road lighting lamps but caps how many may be lit: not more than two of them at any one time, in addition to the two required headlights. A six-pod bar can be fitted, in other words, but Tennessee reads the number of lamps actually burning, not the number bolted on. Subdivision (a)(3) adds an aiming rule that applies to spotlights and auxiliary lamps alike: when approaching another vehicle, no part of the high intensity portion of the beam may be directed beyond the left side of the vehicle carrying the lamp, nor more than one hundred feet (100′) ahead.

Colour is regulated by direction of display, and this is where most aftermarket lighting goes wrong in Tennessee. Subdivision (d)(3) bars any vehicle from carrying steady-burning lights that display to the front in any colour other than white or amber, or any combination other than white and amber. Subdivision (d)(1) is stricter still about flashing: no vehicle may be equipped with flashing lights of any colour displaying to the front, other than the factory installed emergency flashers, unless it appears on the statute's list. That list is specific rather than general, and includes motorcycle escorts of funeral processions authorised under § 55-8-183 to run green strobes, private security service vehicles (any colour except red, white or blue, and only on private premises, never while on a public road), highway maintenance, utility and recovery vehicles running white or amber, organ procurement vehicles carrying an organ for transplantation, school buses, rural mail carriers, and firefighting and rescue vehicles.

Subsection (a)(1) separately forbids any nonemergency vehicle from operating or installing strobe, wig-wag or other flashing systems inside the headlight assembly or grill area, and subsection (b)(1) applies the same ban to the tail lamp, stoplight and factory emergency flasher and backup light areas. The one aftermarket exception written into (b)(1) is the "continuously flashing light system," defined as a brake lamp that pulses rapidly for no more than five (5) seconds when the brake is applied and then converts to a continuous light. Subdivision (b)(4) also permits a white backup lamp that pulses or flashes red during a panic stop while going forward, provided it does nothing on a normal stop.

Tennessee singles out two colours and one direction. Under § 55-9-414(a)(1) it is an offense to install, maintain or exhibit blue flashing emergency lights, or blue in combination with red, except for full-time salaried uniformed law enforcement officers and commissioned Tennessee Bureau of Investigation members; that is a Class C misdemeanor, and the narrow exception for constables reaches only counties inside the population brackets the section sets out, so it is not a statewide allowance. Under § 55-9-415 it is an offense to operate a vehicle equipped with auxiliary lamps or spotlights facing backwards on a road while those lamps are in operation, with emergency and public utility vehicles excepted and lawful use permitted while the vehicle is parked so long as it does not interfere with traffic.

Brightness has its own ceiling. Section 55-9-406(a) requires headlights that render a person clearly discernible two hundred feet (200′) ahead but forbids projecting a glaring or dazzling light at people in front, and § 55-9-408 supplies the measurable test: an anti-glare device, properly adjusted, must keep the bright portions of the beams from rising above a horizontal plane through the lamp centres and in no case higher than forty-two inches (42″) at seventy-five feet (75′) ahead of the vehicle. Rideshare drivers get one narrow allowance in (d)(3)(E): a removable illuminated interior trade dress device in any colour except red or blue, issued by the transportation network company, and not exceeding five candlepower.

00), or both. Displaying blue, or blue with red, without authority is likewise a Class C misdemeanor under § 55-9-414(a)(2). The outlier is § 55-9-415: operating a vehicle on a highway, street or roadway with auxiliary lamps or spotlights facing backwards while they are switched on is a Class A misdemeanor punishable only by a fine of not less than one thousand dollars ($1,000), a mandatory floor rather than a ceiling, and roughly twenty times the maximum for every other lighting offense in the chapter.

Section 55-9-409 gives officers authority to inspect and test lamps suspected of emitting glare and to order illegal lamps removed, and § 55-9-410 penalises refusing or failing to submit to that lamp inspection. Because Tennessee runs no periodic vehicle inspection, all of this is enforced at the roadside, which means an aftermarket bar wired into the grill area is at risk on any stop rather than once a year at a test lane.