Florida vehicle lighting laws

Below are all relevant excerpts from Florida Vehicle Code that limit, restrict or allow certain aftermarket lights including neon undercarriage lighting to be installed on vehicles.

316.215 Scope and effect of regulations

[…] (2) Nothing contained in this chapter shall be construed to prohibit the use of additional parts and accessories on any vehicle not inconsistent with the provisions of this chapter.

This provision is important to note, because it essentially permits using additional lighting equipment as long as it’s not in violation of other regulations.

316.224 Color of clearance lamps, identification lamps, side marker lamps, backup lamps, reflectors, and deceleration lights.

(1) Front clearance lamps, identification lamps, and those marker lamps and reflectors mounted on the front or on the side near the front of a vehicle shall display or reflect an amber color.

(2) Rear clearance lamps, identification lamps, and those marker lamps and reflectors mounted on the rear or on the sides near the rear of a vehicle shall display or reflect a red color.

(3) All lighting devices and reflectors mounted on the rear of any vehicle shall display or reflect a red color, except the stop light or other signal device, which may be red, amber, or yellow, and except that the light illuminating the license plate shall be white and the light emitted by a backup lamp shall be white or amber. Deceleration lights as authorized by s. 316.235(5) shall display an amber color.

316.235 Additional lighting equipment

(1) Any motor vehicle may be equipped with not more than two side cowl or fender lamps which shall emit an amber or white light without glare.

(2) Any motor vehicle may be equipped with not more than one running board courtesy lamp on each side thereof which shall emit a white or amber light without glare.

(3) Any motor vehicle may be equipped with one or more backup lamps either separately or in combination with other lamps, but any such backup lamp or lamps shall not be lighted when the motor vehicle is in forward motion. […]

To stay completely within the law you may want to consider using white or amber lights on the front and front sides of the car, and red lights in the rear sides and rear of the vehicle. Provisions above governing these colors concern other lights (see: Vehicle Light Definitions), but may be interpreted as relevant to neon underglow as well.

316.2397 Certain lights prohibited; exceptions

(1) No person shall drive or move or cause to be moved any vehicle or equipment upon any highway within this state with any lamp or device thereon showing or displaying a red or blue light visible from directly in front thereof except for certain vehicles hereinafter provided.

(2) It is expressly prohibited for any vehicle or equipment, except police vehicles, to show or display blue lights. However, vehicles owned, operated, or leased by the Department of Corrections or any county correctional agency may show or display blue lights when responding to emergencies […]

(7) Flashing lights are prohibited on vehicles except as a means of indicating a right or left turn, to change lanes, or to indicate that the vehicle is lawfully stopped or disabled upon the highway

Penalties

Violation of state laws for vehicle lighting is considered a noncriminal traffic infraction, punishable as a nonmoving violation (316.215).