Vehicle windows must be transparent in order to properly and safely see the roadway, other vehicles, and potential hazards. However, vehicle owners often desire tinted windows for eye comfort and privacy. The rules of all states allow tinted vehicle windows within certain limits. Here are some of the basics on state driving laws governing how, why, and to what extent a driver can tint his or her windows.
Nearly all manufactured vehicles come with some form of window tint. Most rear-windows are semi-transparent, and most vehicles have a tinted area on the top of the windshield to prevent sun glare. But all states limit how and where windows may be tinted.
Federal recommendations. The federal government has issued window tinting recommendations that the states generally follow. Under the federal recommendations, side windows are to be at least 70% transparent and windshields are only allowed to have tinting on the top few inches and stickers in the bottom corners.
Nearly every state prohibits tinting of the front windshield. Those that do permit tinting require at least 70% transparency. All states have an exemption for tinting within the top few inches of the windshield (often called the "AS1 line") but sometimes prohibit yellow, red, or amber color tinting.
Like the windshield, the front driver and passenger windows are generally must be transparent. States that do permit tinting of these windows have limits ranging from 24% transparency to 88% transparency, so check with local rules.
Window tinting is always permitted for windows behind the driver's seat. But the tint limits vary greatly between states. For example, Kansas limits tinting of rear windows to 35% transparency, whereas Michigan has no limit.
Exemption. Drivers with a medically diagnosed photosensitivity medical condition can apply for a permit to exceed the normal tint limits. These exemptions are generally available through the department of motor vehicles and authorize the partial tinting of the windshield and front windows.
Instead of applying a tint, windows can also be coated with a one-way reflective film. This mirror-coat reflects some light, but also prevents anyone from seeing inside of the vehicle, while still allowing the driver to see through the windows. Reflective film is generally prohibited on windshields and most front windows. Some states do allow reflective film on rear windows but generally allow no more than 35% reflection.
Finally, some drivers use window coverings like draperies, decals, and stickers for shade. Generally, these types of coverings are prohibited. However, many states have exemptions for rear window coverings so long as the vehicle is equipped with dual side-mirrors that can show cars approaching from behind and in blind spots.
As tint laws are different in each state, it would be wise to check the rules that are applicable in your area. To make compliance easier, many states also require tint manufacturers to be certified and to place their business information on all installed window tints. This information helps ensure that the tint has been tested and confirms with local regulations.