In Illinois, the legal visible light transmission (VLT) for window tinting is 35% for the front side windows of sedans and 35% or higher for SUVs, vans, and trucks. This means that the tint must allow at least 35% light to pass through the window. The rear window and back side windows do not have any restrictions for SUVs, vans, and trucks. For more information, take a look at the Illinois General Assembly guidelines.