An Englishman is showing two young American girls around London during their holiday. When they reach a Pelican crossing he presses the button, and after a few seconds the pedestrian signal makes the familiar "beep beep beep" sound.
"What's that for?" asks one of the girls.
"Oh, that's just to let blind people know that the lights have changed," replies the Englishman.
"Oh my GAWWWD!" she exclaims, obviously shocked. "In the States, we don't even let them drive!"