Neon lights find uses as advertisements in many businesses but have also become accents to automobiles when placed under the car. While Georgia state law doesn't discuss neon lights in particular, it does regulate the use of certain colored lights on motor vehicles, which would include neon.
Regulations exist in the Department of Transportation Statutes prohibiting the use of blue lights except as part of the stop light assembly, turn signal and rear reflector or hazard lamp. The portion of the stop light on the vehicle must be smaller than one inch in diameter.
Type of Operation
Lighting that operates in a steady or non-continuous mode -- such as flashing or blinking -- is restricted on a motorized vehicle, except standard automobile equipment, unless the vehicle possesses a permit by the state. This statute applies to tow trucks, safety vehicles, police and fire agencies. Neon lights are not standard equipment on any vehicle.
Regulations exist for the operation of blue lights on a moving motor vehicle. However, operation of blue lighting on a vehicle carries no restriction when the car is not moving. If you must have blue neon lighting under your car in Georgia, do not operate it while the engine runs unless you want to risk committing a misdemeanor.