According to FindLaw.com, a global provider of online legal information, the laws and requirements for car window tinting in the United States vary from state to state. Each state's car window tint laws are typically found in its traffic or vehicle code. However, the Federal Motor Carrier Safety Administration (FMCSA) of the U.S. Department of Transportation (DOT) mandates a general regulation for car window tinting.
General Regulation
According to the FMCSA, the tinting or coloring of car windows or windshields to the driver's immediate left and right is allowed. However, the parallel visible light transmittance through the tint should not be less than 70 percent, which is the typical occurrence percentage of visible light transmittance. This constraint does not apply to the other windows of a car.
If you are uncertain about a vehicle's tint legality, a certified inspector can make the determination using a special measuring device. According to FindLaw.com, your state's Department of Motor Vehicles (DMV) can advise you on the best place to have a vehicle inspected in your state. If you move to a new state, it is best to check the new state's specific laws, in case they differ from those of the state you are moving from.
Examples
According to the International Film Window Association (IFWA), an international membership association for window film manufacturers, Alabama, California and Washington car window tint laws were enacted in 1996, 1999 and 2000, respectively. The types of window tint the laws pertain to are net tints for Alabama and California, and film tints for Washington.
To further illustrate the differences of car window tinting laws in various states, California strictly follows the 70 percent of visible light transmittance law for both windshields and windows, while Washington and Alabama allow lower visible light transmittance percentages of 35 and 32 percent, respectively, for windows and a small section of the windshield.
Alabama and Washington also require a certificate from tinting shops to verify that tints meet the state laws, while California does not. On the other hand, one requirement these states share is the presentation of a medical document for drivers or passengers that require darker tints for medical reasons.
Medical Exceptions
States such as Washington, California and Alabama allow the installation of darker car window tints, provided the owners can produce medical certificates. Examples of medical conditions that meet the criteria of the medical exception, include melanoma, lupus and photosensitivity. Vision-related medical conditions may also qualify under the exception.
