(CBS News) It's a code all drivers share: A flash of the high beams is a warning there's a speed trap ahead.

But when police in Florida saw one man doing it, he got slapped with a $115 speeding ticket.

His case was overturned, but in some states, it is illegal to warn other drivers there is a speed trap ahead. Arizona and Alaska forbid flashing of high beams, while the states of New Jersey, New York, Ohio, Pennsylvania, Tennessee and Virginia allow it.

In London and Cornwall, a pilot program has just been launched that combines all the fun of terrestrial speed cameras with the creepy omniscience of GPS. In a nutshell, the program -- called "SpeedSpike" -- uses positioning satellites to track motorists as they travel between traffic cameras. By calculating the time it takes a driver to move from one point to the other, SpeedSpike can determine whether or not the motorist has been speeding.