[Red Sea Swimmer]

In my late teens, I knew a guy who one night when he was bored went out (dressed in an official looking outfit) to the side of a busy road with a hairdryer and aimed at the oncoming traffic. He had instant success as the traffic slowed down and many people told him to...

"Go back to the Hairdressers".

(The words shouted by the drivers passing him were not exactly those kind, advisory, if you know what I mean.)

It's amazing what fun he had with just one hairdryer.

[Larry Lucido]

I don't think the doppler effect is as pronounced with a hair dryer as it is with a radar gun. For one thing, the hair dryer really needs to be plugged in, and even a gentle breeze can cause a false reading. There is a low conviction rate on hair dryer tickets.

[Ichneumon]

to the side of a busy road with a hairdryer and aimed at the oncoming traffic

Science repeats itself: http://www.netroglycerine.com/surprise4.html.