SAN DIEGO (KSWB) — Window tinting is popular among many drivers. But what’s legal and what’s not in California?

“The purpose of having the window tint law is basically, you don’t drive at night with your sunglasses on, and that’s essentially what you’re doing with 40% of your vision,” California Highway Patrol Sgt. Brian Pennings told FOX 5 Wednesday.

Pennings says tinted windows have been a factor in collisions due to drivers being unable to see out of their vehicles.

“It’s a safety issue, and lawmakers in California have decided to keep this law on our books,” Pennings added.

Rear windows

Drivers can tint their rear windows as long as their vehicle has two side mirrors, not including the rearview mirror, Pennings said.

Front windows

When it comes to front windows, California law states drivers must have 70% transparency, meaning they can have 30% tint, Pennings said.

What window tint shops may not tell their customers, Pennings says, is that window glass has nearly 30% tint already in it when it comes from the factory. So when an additional 30% tint is added, that makes for an illegal amount of light transparency.

Front windshields

Drivers can tint their front windshields under certain circumstances — but Pennings says there’s a mathematical formula to apply.

“Put the driver’s seat all the way back, measure four inches out from the back and the bottom, and then measure 29 inches up, and it can’t cross that horizontal plane,” Pennings says. “The rule of thumb that most people use is four inches … If it’s within four inches of the top of the windshield, then typically, you should be safe.”

Potential exceptions

A doctor’s note does not allow drivers to permanently tint their front windows. Drivers with a doctor’s note can, however, put up a temporary shade, but it must be readily removable, according to Pennings. The reason is, if the person is driving when it’s dark and shade is no longer required, they must be able to remove it. In addition, if someone without a doctor’s note drives the car, they must be able to take it down.

Patients with skin cancer, for example, can put a legal film on their front windows for UV protection, but the film must have 88% transparency. The film must be installed by a certified dealer, and drivers must have a certificate of authenticity in their possession.

What about drivers in California on vacation? If a vehicle is legally registered in another state, then the vehicle falls under the mechanical guidelines of that state, Pennings said.

Colored tint

It is illegal in California to tint windows red, blue or amber.


Violators of California’s window tint laws may be issued a fix-it ticket, but for repeat offenders, it could be construed as a failure to comply with the law, which could be a misdemeanor, Pennings says.

“Also, you have some potential liability if you’re involved in a crash because your vehicle is illegally equipped,” Pennings said.