A truck driver was driving along on the freeway. A sign comes up that reads "Low bridge ahead!" Before he knows it, the bridge is right ahead of him and he gets stuck under the bridge. Cars are backed up for miles. 

Finally, a police car comes up. The cop gets out of his car and walks around to the truck driver, puts his hands on his hips and says, "Got stuck, huh?" 

The truck driver says, "No, I was delivering this bridge and ran out of gas."