All states have traffic laws that limit the amount of window tint on motor vehicles—often by specifying the amount of visible light transmission (VLT) that is required. VLT is the amount of light that is transmitted through the window and into the vehicle. For example, a 70%VLT means that 70% of light will pass through the window and 30% will be reflected. Thus, a lower VLT indicates a darker film or tint.

Another term to know is visual light reflection (VLR)—which is the opposite of VLT. VLR is the amount of solar energy that is reflected off the glass and away from the inside of the vehicle.

In most states tickets or citations for illegal window tint are known as fix-it tickets and the ticket or citation will indicate that it is a correctable violation of traffic laws. For example, if you fix the window tint problem within the required period, pay a small fine, and get the signature of an authorized person (a local police officer) the court may dismiss the ticket.

But if you fail to fix the window tint problem within the required period you must pay the fine for the violation and you may be issued another ticket that will be part of your driving record. And if you fail to pay the ticket or appear in court on the hearing date the court may issue a warrant for your arrest.

Window tint laws vary from state to state and some states have exemptions for certain vehicles such as limousines and recognize medical exemptions when the driver has a written statement from a licensed medical doctor, ophthalmologist, or optometrist.

In Colorado, window tint laws are designed to ensure that visibility through vehicle windows is not excessively restricted. The state specifies the amount of visible light transmission (VLT) that must pass through the window tint on motor vehicles. Colorado law requires that the front side windows must allow more than 27% of light in (27% VLT), and the back side and rear windows can have any level of darkness. The windshield may have non-reflective tint above the manufacturer's AS-1 line. Reflective tints are also regulated, with Colorado stipulating that front and back side windows must not be more than 27% reflective. Medical exemptions are available for individuals who require less light exposure for medical reasons, and they must carry documentation from a licensed physician. Violations of window tint laws in Colorado are typically treated as 'fix-it' tickets, which are correctable violations. If corrected within a specified period and verified by an authorized person, such as a local police officer, the court may dismiss the ticket upon payment of a small fine. Failure to comply within the required period can result in fines and additional tickets, which may affect one's driving record. Non-compliance with court directives, such as failing to pay a fine or appear in court, can lead to a warrant for arrest.