Flat Tire?

This man at the side of the road was fixing his flat tire. A police car stops behind his and the officer strolls to him to offer help. The man says he's doing OK and doesn't need help.

The officer takes a walk around the car to make sure everything is OK. He spots a large knife with a fancy handle on the passenger seat. When he asks about the knife, the man says it's his and he uses it as a juggler at the local circus.

The officer then asks him to demonstrate his act to be sure the man is telling the truth, and the man goes through his routine.

Meanwhile a car with two recovering alcoholics drives by. The driver says to his passenger, "Man ... I am glad I stopped drinking when I did. It's amazing what they make them do these days at those roadside sobriety checks!"