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 Montana (MT), window tinting on motor vehicles is regulated under state law, which specifies the amount of visible light transmission (VLT) allowed. The VLT percentage indicates how much light is allowed to pass through the window. Montana law requires a minimum VLT of 24% for the front side windows and 14% for the back side and rear windows. The front windshield may have a non-reflective tint strip on the top four inches. The state also regulates visual light reflection (VLR), allowing a certain percentage of light to be reflected by the window tint. Montana does provide exemptions for certain vehicles and individuals with medical conditions that necessitate darker tints; such individuals must carry documentation from a licensed physician. Violations of window tint regulations are typically considered correctable violations, meaning that if the issue is rectified within a specified period and verified by an authorized person, such as a police officer, the citation may be dismissed upon payment of a dismissal fee. However, failure to comply with the correction requirement or to pay fines can result in additional penalties, including the possibility of a warrant for arrest if a court appearance is missed.