[ossiblue]

There are two issues, at least here in California. One is the color of the lens, the other is the red reflector. Rear lenses can be tinted (legally) if they they still produce a red light when the lights are on. However, there must always be a red reflective lens at the rear of the vehicle. This is the issue which gets most people into trouble because most modern cars have the red reflector integrated into the light lens and when they tint the lens, they also tint the red reflector.

c) All lamps and reflectors visible from the front, sides, or rear of a vehicle, except headlamps, may have any unlighted color, provided the emitted light from all lamps or reflected light from all reflectors complies with the required color. Except for backup lamps, the entire effective projected luminous area of lamps visible from the rear or mounted on the sides near the rear of a vehicle shall be covered by an inner lens of the required color when the unlighted color differs from the required emitted light color. Taillamps, stoplamps, and turn signal lamps that are visible to the rear may be white when unlighted on vehicles manufactured before January 1, 1974.