Accuracy matters

Chocking through some back issues of Computing I was amused to come across a story featuring Dr Phillip Tann who was booked by Sunderland police for doing 42mph in a 30mph, by sheer coincidence (and luck on his part) Dr Tann was testing a piece of equipment that measures exact locations and speed to a high degree of accuracy. When I say high the case was dropped when he revealed he was travelling at 29.177196 mph a reading accurate to within a tenth of a millimetre per hour. Bit of a difference from 42mph eh?