Ask a troooper: Shining some light on window tinting

May 8—Question: If a person has a medical exception to a specified window tint level (per medical prescription by medial provider), do you have to register that exception/prescription with the state? Or register the car that has the applied tint?

Answer: It is not necessary to notify the Department of Public Safety Driver Vehicle Services in Minnesota. DVS doesn't place window tint/medical restriction on the driver's license or on the vehicle's registration. Drivers will need to have a prescription or proof from their doctor regarding the medical need to have tinted windows below the 50 percent light transmittance plus or minus 3 percent.

The proper document will need to be in the vehicle to show law enforcement upon request. The document will need to specifically state the minimum percentage that light transmittance may be reduced to satisfy the prescription or medical needs of the patient; and the prescription or statement contains an expiration date, which must be no more than two years after the date the prescription or statement was issued.

If the window tint is below the state minimum of 50 percent light transmittance, that vehicle may be stopped by law enforcement, as the officer will not be aware of the medical exemption.

In Minnesota, you can have your windows tinted to a light transmittance of 50 percent but not less. Light transmittance is the amount of light that is required to pass through both the window and the tint film.

Before any tint material is applied to your windows, a vehicle comes from the factory with tint already inside the glass material. No window comes from the factory at 100 percent light transmittance. My experience has been that most vehicles are already at 75 percent before any modifications.

—No vehicle can have any tint to the front windshield.

—Passenger cars are limited to 50 percent on all side and rear windows.

—Pickups, vans, and SUVs are limited to 50 percent on the front side windows.

—Pickups, vans, and SUVs are not limited on the rear side and rear windows (can be less than 50 percent behind the front seat).

—Squad cars, limousines, and vehicles used to transport human remains by a funeral establishment are not limited on the side and rear windows.

Troopers have window tint meters in their patrol cars and will test the windows for the legal percent of light transmittance if they look to be below the statutory limit. If they are found below the legal limit, the driver may be issued a citation.

You can avoid a ticket — and a crash — if you simply buckle up, drive at safe speeds, pay attention and always drive sober. Help us drive Minnesota Toward Zero Deaths.

Any questions concerning traffic related laws or issues in Minnesota, send your questions to Trooper Troy Christianson, Minnesota State Patrol, 2900 48th St., NW, Rochester MN 55901-5848; or send an email to: Troy.Christianson@state.mn.us.