Darkness of tint is measured by Visible Light Transmission percentage (VLT%). In California, this percentage refers to percentage of visible light allowed in through the combination of film and the window.
• Windshield - Non-reflective tint is allowed on the top 4 inches of the windshield.
• Front Side Windows - Must allow more than 70% of light in.
• Back Side Windows - Any darkness can be used.
• Rear Window - Any darkness can be used.
HOW REFLECTIVE CAN THE TINT BE IN CALIFORNIA?
Similar to sunglass lenses, some tinting film contain metallic elements that help in reflecting incoming light and reducing the glare and heat generated by visible light.
• Front Side Windows - Must not be more reflective than a standard window.
• Back Side Windows - Must not be more reflective than a standard window.
OTHER CALIFORNIA RULES AND REGULATIONS
• Restricted Colors - The tint color(s) of RED are not legal by state law.
• Side Mirrors - Dual side mirrors are required if back window is tinted.
• Certificate Requirements - Manufacturers of film do NOT need to certify the film they sell in the state.
• Sticker Requirements - No sticker to identify legal tinting is required.
• Medical Exemption - State law does NOT allow medical exemptions that would allow you use special tint.