Ask a Trooper
Question: Are smoked tail lights illegal in Minnesota?
Answer: Minnesota law states that “tail lamps shall be plainly visible from a distance of 100 feet to the rear during normal sunlight and at night.” The same goes for turn signals and headlights. Smoking, tinting, covering or placing any material over tail lights, brake lights, headlights or turn signals would be illegal and unsafe as they would not be plainly visible. It is illegal in all 50 states, because it is a major safety concern.
I recommend getting into the habit of checking and keeping your rear lights clear of any snow, mud, dirt, dust or anything that can obstruct your lights.