It is very important for other drivers to be able to see you, for for your own safety. I need to see if you are alert and see me, or are distracted by something else. With normal tint, I can see that you are not going to pull out in front of me because you are looking at me. Drivers with dark tints do not have this safety net for their mistakes. Also, it can easily raise the tension level in any encounter with the police, because they can't see you. I don't need to give them any reasons for being more aprehensive with me or my car.