I'n not sure if this is an urban myth, because it actually appeared onn Arthur.C.Clarke's Mysterious World as well as in the book that accompanied the series, but I suspect it is, I shall explain after the story:
This concerns a driver who was going home after a night with some friends. He was driving along the road when he saw a female hitchhiker. He stopped and asked where she was going, she told him. It was on his way so he gave her a lift. She wasn't very talkative so he never got much information out of her. At one point he turned round to ask her a question, and she was no longer there! Suffice to say he went stray to his local and had a few stiff ones.

Okay to explain why I don't know if this is a FOAFtale or not. I heard this story some years ago, I was interested because it happened near me, in a small town called Dunstable. About a year after the programme I was going out with this girl from Dunstable and we were having a pretty good time. When one night we were talking and I told her the above story, she went all quiet and moody. It turns out that the man in question was her Uncle and that ever since that night, he had the piss taken out of him buy all his mates at the pub ( The Windsock which no longer exists). I met her uncle, a nice bloke. What calls into question the veracity of the story is the fact that I have heard the same or similar stories over the years, in different parts of the world.
FOAF=( Friend Of A Friend)