Underglow Laws: Everything You Need to Know

The National Landscape

If you're shopping for LED underglow kits, here's the headline: no state flatly bans underglow, and no state gives it a clean, unconditional green light either. Every single one of the 50 states falls into a "conditional" category — meaning underglow is legal only within specific limits on color, flashing behavior, brightness, or where and when it can be lit.

That 0 legal / 50 conditional / 0 illegal split tells you something important: underglow regulation in the U.S. isn't really about banning aesthetic lighting outright. It's about controlling three things almost universally — red light shown to the front (which can be confused with emergency or hazard signals), blue light (reserved for law enforcement in nearly every state), and flashing, rotating, or oscillating effects (reserved for emergency, school bus, and utility vehicles). States that allow underglow "including while driving" almost always still forbid these three things.

A smaller cluster of states takes a stricter structural approach: rather than permitting underglow with color/behavior limits, they prohibit any non-factory lighting from being lit while the vehicle is on a public road at all, only allowing it on private property.

See the full 50-state comparison

States That Allow Underglow While Driving (With Conditions)

The majority of states — roughly 38 of them — permit underglow to be used while the vehicle is in motion, provided it stays within color and behavior rules. Typical restrictions in this group include no red (or red/blue) visible from the front, no blue at all, and no flashing.

States in this category include Underglow in Alabama, Underglow in Arkansas, Underglow in Delaware, Underglow in Florida, Underglow in Hawaii, Underglow in Idaho, Underglow in Indiana, Underglow in Iowa, Underglow in Kansas, Underglow in Kentucky, Underglow in Louisiana, Underglow in Maryland, Underglow in Mississippi, Underglow in Missouri, Underglow in Montana, Underglow in Nebraska, Underglow in Nevada, Underglow in New Hampshire, Underglow in New Mexico, Underglow in North Dakota, Underglow in Ohio, Underglow in Oklahoma, Underglow in Oregon, Underglow in Rhode Island, Underglow in South Carolina, Underglow in South Dakota, Underglow in Tennessee, Underglow in Texas, Underglow in Utah, and Underglow in West Virginia, among others.

The pattern across nearly all of them: white or amber to the front, red to the rear, no blue, no flashing. Get those four things right and underglow is fair game almost everywhere in this group.

States That Prohibit Underglow While Driving

A distinct group of ten states takes a harder line: rather than regulating underglow by color, they treat any non-required, non-permitted lighting as something that must stay dark on public roads, period. Underglow is only legal parked on private property in Underglow in Connecticut, Underglow in Illinois, Underglow in Maine, Underglow in Massachusetts, Underglow in Michigan, Underglow in Minnesota, Underglow in Pennsylvania, Underglow in Virginia, Underglow in Washington, and Underglow in Wisconsin.

Two more states land in a gray zone worth knowing about. New York treats steady-burning white as the only safe civilian underglow color, effectively restricting colored or flashing accent lighting on the road. Vermont doesn't ban steady accent lighting outright, but bars blue light of any kind without a permit and bans non-emergency flashing in any color other than amber — meaning red or blue displays will fail inspection without a permit under its statute.

Notable and Unusual Rules

A few states stand out for rules that go further than the standard "no red, no blue, no flashing" template.

Colorado doesn't just restrict how red and blue lights are used — it restricts whether you can even own the hardware. Colorado law provides that "a non-emergency vehicle may not even carry a lamp capable of showing red or blue from directly in front," a violation classified as a class 2 misdemeanor. (C.R.S. §§ 42-4-238, 42-4-213(4), 42-4-215)

North Carolina has a similar hardware-level restriction on blue: it's banned "even possessed on the vehicle," not just when lit. (N.C.G.S. § 20-130.1)

California is one of the few states with a precise photometric standard rather than a vague "not too bright" rule. Underglow there must stay diffused and dim — capped at 0.05 candela/sq in with a maximum total area of 720 sq in — and must not show red toward the front or flash. (Cal. Veh. Code §§ 25400, 25950)

Illinois backs up its total prohibition with real teeth: unauthorized oscillating, rotating, or flashing lights are a Class A misdemeanor even when unlit. (625 ILCS 5/12-201 et seq., 5/12-215)

South Dakota caps the hardware itself, limiting drivers to no more than three auxiliary lamps, with red-to-the-front or blue-anywhere violations charged as a Class 2 misdemeanor. (SDCL §§ 32-17-9, 32-17-42, 32-17-17, 32-17-20)

Arizona pairs its color rules with a specific brightness and aiming standard: lamps over 300 candlepower must be aimed within 75 ft, and no more than 4 such front lamps may be lit at once. (A.R.S. §§ 28-946(B), 28-947(A)-(C))

Vermont singles out low-intensity accessories too — "reflector-equipped devices over 4 candlepower need Commissioner approval during lighting hours." (23 V.S.A. §§ 1251, 1254, 1246, 1253)

The Common Threads

Zoom out across all 50 states and three restrictions show up almost everywhere, regardless of whether a state is in the "allowed while driving" camp or the "private property only" camp:

• Red to the front is almost universally restricted or banned — it reads too much like a warning signal in a rearview mirror.
• Blue is nearly always reserved for law enforcement, sometimes so strictly that merely equipping the lamp is a violation, not just using it.
• Flashing, rotating, or oscillating effects are reserved for authorized emergency, school bus, or utility vehicles in almost every statute reviewed, whatever the state's stance on steady colored light.

If you keep your underglow steady, avoid red facing forward, skip blue entirely, and check whether your state requires lights to go fully dark while driving, you'll be compliant in the overwhelming majority of jurisdictions.

Every state page has the exact limits, statute citations, and exceptions — free.

This guide was compiled using AI-assisted extraction and summarization of state statutes and regulations. While every effort has been made to verify accuracy against primary sources, laws change and interpretations vary — always confirm current requirements with your state's motor vehicle code or a local authority before modifying your vehicle.