A speed camera installed during roadworks on the M6 has caught more than 5500 speeding motorists in just five weeks.
The camera, sited between junctions 43 and 44 of the M6 Carlisle and installed to protect workers during road repairs, is said to have brought in over £160,000 in fines so far - and it still has another two weeks to run.
Kevin Tea, manager of Cumbria Safety Cameras, said, "In seven years working on the safety partnership in Cumbria, never have I seen a camera generate so many tickets.
"I can't offer an explanation for it. I can't understand why people haven't seen the signs and are continuing to speed."
Only those motorists who were caught at more than 60mph in the 50mph zone are likely to be fined - but that could still mean almost 3000 motorists facing penalties.
Clare Armstrong from anti-speed camera group Safe Speed said, "We're pretty disgusted. It's obviously got nothing to do with road safety.
"The fact that it's raising so much revenue will add to the police/public divide and continue to make people believe it's just about making money. You don't measure safe driving in miles per hour."