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 South Dakota, traffic laws regulate the amount of window tint on vehicles by specifying the required Visible Light Transmission (VLT). South Dakota law mandates that the front side windows must allow more than 35% of light in. The back side and rear windows can have any level of darkness. The state also specifies that the window tint reflection for front and back side windows must not be more than 20% reflective. These regulations are in place to ensure that drivers have sufficient visibility while driving. If a vehicle is found to have illegal window tint in South Dakota, the owner may receive a 'fix-it' ticket, which is a correctable violation. The owner must then remove or replace the tint to meet legal standards, pay a fine, and have the correction verified by an authorized person, such as a local police officer. If the issue is not corrected within the specified period, the owner may face additional fines and the violation could become part of their driving record. Failure to pay the fine or appear in court may result in a warrant for arrest. South Dakota also recognizes medical exemptions for window tint if a driver has a written statement from a licensed medical doctor, ophthalmologist, or optometrist.