Could you be breaking the law without even knowing it?
Diesel trucks usually leave black smoke behind, but when they let out excessive smoke, it becomes a problem.
This is also known as blacking out and is illegal.
Wyoming Highway Patrol Troopers say reduced visibility from the smoke is their biggest concern.
Police will pull you over if they see it.
It's a part of a state statue requiring an exhaust system to filter excess noise and smoke.
Troopers say Wyoming citizens want them to concentrate on distracted driving, but this falls into that category.
Captain Shawn Dickerson has some advice for anyone thinking of adding an exhaust to their car.
"I would just recommend that they think twice before doing it and understand that when they're applying heavy acceleration and it's spewing out black smoke, they are in violation of state statue."
Dickerson urged if you see any sort of distracting behavior on the road, call the police.