its a bit gray area. There is some vechical codes that allow film that transmits 70% light or more.... but I dont know if it is restricted for medical use or anything. I got the lightest shade which is like around 70% so I figure I'd try to use that if I get ticketed... and since my rears are so dark (like 30%), its harder to tell my front is tinted since its like 70% in the front.