[vanman]

The number of drivers speeding past Oxfordshire's deactivated speed cameras has increased by up to 88%, a road safety partnership claim.

I assume that the survey that was done using a hand held LTi 20-20 speed gun which seems to be inaccurate.
http://www.bbc.co.uk/insideout/south...-cameras.shtml

The slip effect
diagram showing the slip effect
If the laser doesn't focus on the same area you can get the slip

As the gun calculates speed by measuring the changing distance to a car, if the beam of the gun is moved along the car while taking a reading, this could affect the results.

http://www.youtube.com/watch?v=q9BgKebdgWE
http://www.youtube.com/watch?v=CbNmD...eature=related

Case One: Paul Cox

Paul Cox
Paul appealed against his speeding conviction and won

Paul Cox was driving towards Plymouth on the A303 Dual carriageway when he was stopped for speeding.

The car he was driving was fitted with cruise control, which he had set to just below 70mph - the speed limit on that stretch of road.

He passed by a marked police car that was carrying out speed checks and was asked to pull over.

The police told Paul that they had clocked his speed as being in excess of 90mph.

He was confident that he had not broken the speed limit and contested the case in court.

Former policeman Paul Cox appealed against his conviction – and won. The court found there were discrepancies in the speed gun evidence used against him.

Paul had the confidence to contest his case, but many simply accept the fines even though they feel they are in the right.