Ala. Code § 32-5C-6
Any motor vehicle which has material and glazing applied or affixed to the windows or rear windshield of a vehicle, which material and glazing have reduced the light transmission through the window or windshield or increased the light reflectance of the window or windshield, shall display a label visible from the outside of the vehicle indicating that the windows and windshield are in compliance with the light transmission and light reflectance requirements as provided in Section 32-5C-2. No person shall install any material upon the windshield or windows of any motor vehicle, the installation of which would result in a reduction of light transmission or an increase in light reflectance in violation of Section 32-5C-2.
Ala. Code § 32-5C-6 (1975)