Thinking about adding underglow to your car? Here is what California law says, and how to run it legally. If you are ready to install, see our RGBIC underglow kit and the step-by-step install guide.

Is Underglow Legal in California? (2026 Guide)

Two rules are nearly universal across the US: no red light shown to the front and no blue underglow (both are reserved for emergency vehicles), and no flashing, rotating, or strobing lights while driving. Beyond that, states differ. Here is how California handles it.

Underglow rules in California

• Colors: No red light may be shown to the front. Avoid blue as well, blue and red are associated with emergency vehicles. Amber, white, and green are common safe choices.
• No flashing: The lights may not flash, strobe, rotate, or oscillate.
• Brightness and placement: The light must be diffused and non-glaring, and must not be mounted within 12 inches of, or interfere with, any required lamp or reflector.
• Driving vs parked: Compliant underglow (steady, no red to front, non-glaring) is generally treated as usable on the road, though enforcement varies by officer.

Underglow while parked or on private property

These laws generally govern vehicles on a public road or highway, so on genuinely private property, a private parking lot, driveway, car show, or off-road, underglow use is usually far less restricted. It is not a blanket "legal when parked" rule, though. A car parked on a public street is usually still treated as being on the highway, so the color limits (no red or blue to the front) and equipment rules still apply. Red or blue lighting can also trigger separate police-impersonation laws based simply on having or using it, whether or not the car is moving. When in doubt, keep to compliant colors and check your local ordinances.

How to stay legal with underglow in California

• Keep the lights steady-burning, never flashing, strobing, or rotating.
• Show no red light to the front, and avoid blue entirely.
• Do not mimic emergency-vehicle lighting or obscure your license plate.
• Confirm the current rule below and check locally before driving with it on.

The law

California Vehicle Code section 25400 (verified against the official California legislative text). Related color rules appear in section 25950. You can read the referenced law here: California statute.

Ready to install?

Our RGBIC underglow kit lets you dial in any color and keep it steady, and the install guide walks through wiring it to a switched power source. Free shipping on all US orders.

California Underglow FAQ

Can I drive with underglow in California?
Generally yes, if it is steady-burning, shows no red to the front, and is diffused and non-glaring. Enforcement can vary by officer.

What underglow colors are illegal in California?
No red to the front, and avoid blue (both are emergency-vehicle colors). Flashing or strobing of any color is not allowed.

Can I have underglow on while parked in a lot?
On genuinely private property, such as a private lot, driveway, or car show, underglow use is generally far less restricted. On a public street a parked car is usually still treated as being on the highway, so the color rules still apply, avoid red and blue, and check your local ordinances.

Updated July 2026.