Underbelly neon and colored vehicle lights are sold in Tennessee and are not illegal to be attached to your car or truck. Such lighting modifications are permitted for use off-road and/or on personal property only. Lighting regulations according to Tennessee's statutory code, title 55, states that no such modifications may be used on state thoroughfares. This includes state roads and highways. Emergency, law enforcement and "help" vehicles, such as tow trucks, are exempt.
Emergency response vehicles are permitted colored lighting. Personal vehicles on state thoroughfares are not. Fire and EMS vehicle lights are either red or red and white. Law enforcement personnel use blue or blue and red lights on their vehicles. White lights are used in tandem with red and/or blue emergency vehicle lighting.
Personal/Other Business Vehicles
Security personnel vehicle lights are green and tow trucks, construction, funeral and other maintenance vehicles use amber or yellow lights. No personal vehicle may use neon or colored lights on public thoroughfares that emulate emergency vehicle lights. Flashing or strobe lights, wig-wags or underbelly neon lighting is prohibited.
Infractions may be cited by ticket or fine, or be classed as a "C" misdemeanor. A class "C" misdemeanor warrants "not greater than thirty (30) days in jail or a fine not to exceed fifty dollars ($50.00), or both, unless otherwise provided by statute."