Still counting down the list of best smart answers. This one is #2:
A truck driver was driving along on the freeway and noticed a sign that read: Low Bridge Ahead. Before he knows it, the bridge is right in front of him and his truck gets wedged under it. Cars are backed up for miles.
Finally a police car comes up. The cop gets out of his car and walks 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 I ran out of gas.'