Usage of neon underglow lighting is governed by Michigan Vehicle Code, Chapter 257: Motor Vehicles, Act 300: Motor Vehicle Service and Repair Act, Section 257.698.
Is neon underglow legal in Michigan?
Michigan law explicitly prohibits additional vehicle lighting while the vehicle is on public roads. Therefore it’s our conclusion that in Michigan neon underglow is illegal while driving.
You may install car underglow as long as the lights are covered and not lit while driving.
Furthermore it is forbidden to use any kind of flashing lights. Legally only permitted colors for aftermarket lighting is white or amber in the front and front sides, and red or amber in rear and rear sides of a vehicle.
Installing underglow in state of MI is not illegal, but ensure you use it only on private property.
Michigan vehicle lighting laws
Below are all relevant excerpts from Michigan Vehicle Code which restrict certain aftermarket lights to be installed on vehicles.
Michigan Vehicle Code, Section 257.698
(4) Unless both covered and unlit, a vehicle operated on the highways of this state shall not be equipped with a lamp or a part designed to be a reflector unless expressly required or permitted by this chapter or that meets the standards prescribed in 49 CFR 571.108. A lamp or a part designed to be a reflector, if visible from the front, shall display or reflect a white or amber light; if visible from either side, shall display or reflect an amber or red light; and if visible from the rear, shall display or reflect a red light, except as otherwise provided by law.
(5) The use or possession of flashing, oscillating, or rotating lights of any color is prohibited except as otherwise provided by law, or under the following circumstances: [police vehicle, fire vehicle, ambulance, authorized emergency vehicle, ...]
Michigan Traffic Law FAQs
Michigan’s Traffic Law FAQs (link) also include specific answers about neon underglow. Below are the relevant questions and answers which explain the usage of neon lighting on cars and other vehicles.
Question: Can I install neon lighting within the interior of my vehicle?
Answer: The problem with placing neon lighting inside a vehicle is that the vehicle code is very specific about the color of lamps allowed on a vehicle and what color can be seen from what direction. For instance, the only color legally allowed to be displayed to the front of a vehicle is white or amber. The only color allowed to be displayed to the rear is red or amber. To the sides, front – amber or white, rear – amber or red. No other colors are allowed and if any permitted color lamp is visible from any direction that is not allowed then it cannot be equipped that way. If the lighting causes a visual impairment for the driver or is potentially distracting then such lighting is unlawful. Finally, like exterior neon lighting, there is no provision within the Michigan Vehicle Code that allows the use of interior neon lighting. Ultimately it will be a matter for the courts to decide.
Question: Can I have neon underbody lighting on my vehicle?
Answer: MCL 257.698(4) prohibits equipping a vehicle with any lighting that is not expressly required or permitted by Chapter 6, unless both covered and unlit. Neon underbody lighting is neither expressly required nor permitted. If equipped, the lights must be unlit and covered while on a highway, which includes all public roads and the adjacent rights-of-way.
Question: I am considering equipping my vehicle with neon valve stem lights. Are they legal?
Answer: If installed on a vehicle, the lights must be both covered and unlit while on a highway (any public road, including the right-of-way). This prohibition includes, but is not limited to: windshield wiper lights, tire valve stem lights, overhead/roll bar lights, underbody lights, and interior after-market lighting if visible from outside of the vehicle.
As per Michigan Vehicle Code Section 257.698, violation of vehicle lighting laws is a civil infraction.
(9) A person who operates a vehicle in violation of subsection (1), (2), (3), or (4) is responsible for a civil infraction.