Neon Underglow Laws

California Neon Underglow Lights Laws

Neon or more popularly called underglow lights are very popular among car enthusiasts looking to improve their car’s appearance. Though safety issues are less talked about with underglow lights, most car (or even motorcycle or truck) owners attach neon lights to their vehicles simply to make them look cooler.

Most states restrict color or luminosity or neon lights attached to the car, among other things. Enthusiast drivers can take things too far sometimes, so to ensure other drivers don’t get distracted by overly flashy vehicles there are legislation to prevent various modifications. For neon underglow, most of these laws are found under “Unlawful vehicle modifications” and “Lighting requirements”.

In the state of California (CA), neon underglow lights are legal to use, but with some crucial restrictions you must be aware of. Below you can find the basic overview of guidelines pertaining to neon car lights in California.

Light emission

California’s Department of Motor Vehicles (DMV) allows LED lights which emit a diffused non-glaring light which is less than 0.05 candela per square inch (1 candela is essentially equal to the light emitted from one candle). Check your neon lights’ luminosity when buying them to make sure they’re within California DMV standards.

Size and position

There are several other restrictions on size and position of neon lights attached to your vehicle:

  • Lights must not replace or disrupt any of your vehicle’s required existing lights (such as tail lights, break lights, turn signals, or headlights)
  • Neon lights must not be installed within 12 inches of any required light, lamp, reflector or other required device on your vehicle
  • The size of the underglow must not be larger than 720 square inches, unless your vehicle is authorized to display signs.
  • Additionally, internally illuminated sign in your vehicle is permitted if it’s less than 0.25 candela per square inch, must not contain a white background, and may only be displayed on each side but not on front or rear of your car.

Restricted colors

According to California underglow laws your vehicle may not display red color at the front of vehicles. Though most states restrict colors such as blue or red since it may appear like a police vehicle, in California you can use any colors for the underglow (other than red restriction on the front of your car).

Though not specifically forbidden, it’s always best to avoid using any kind of flashing lights, in order to avoid distracting other drivers or being mistaken as a police vehicle.


Underglow system which is outside the law may result on you getting cited for a non-moving traffic violation, in which case you will be required to modify your car to conform to standards, as well as pay a fine.

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This article about California Neon Underglow Lights Laws was last updated in 2024. If any of our information is incomplete or outdated please let us know. Thank you!