But when he saw the second flash in his rear view mirror he knew something was wrong.
For Michael Knott had driven past the speed camera on Chester Road in Mere at 45mph - 5mph under the speed limit.
"My brother-in-law had been caught out by the same camera just a couple of weeks earlier," he said.
"But I was surprised that it got me too. There seems little point in having it there if it catches people who aren't speeding."
Once he reached his destination he telephoned police to report the fault.
"I was told that other people had complained but not to worry because there was no film in the camera anyway," he said.
"Surely that's not the point."
On Monday a police spokesman told the Knutsford Guardian that some lorry drivers had logged complaints about the same camera.
But that did not solve Mr Knott's mystery - he drives an Audi car.
"My car may be big, but it's not in the same league as a lorry," he said.
"And it shouldn't matter what type of vehicle goes past - it should only catch those over the limit."
Another camera on the same road in Tabley seems to be causing similar problems.
A Guardian reporter drove past it on Saturday whilst travelling at around 50mph.
The limit on that stretch is 60mph, but the camera flashed regardless.
"I wonder how many other people have been caught driving safely on that road," said Mr Knott.
Police said yesterday (Tuesday) that the faulty camera in Mere will checked as soon as possible.
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