Only about half of those caught speeding will be fined
Road safety bosses say they are stunned after a speed camera caught out more than 5,500 motorists in five weeks.
The camera, on the M6 near Carlisle, was installed to protect workers carrying out repairs and is expected to net £168,000 from fines issued so far.
A Cumbria Safety Cameras spokesman said he could not understand why so many drivers are ignoring the 50mph limit, which is clearly signposted.
Pressure group Safe Speed called the figures "disgusting".
The camera was installed between junctions 43 and 44 of the M6 on 29 January and will stay while bridge repairs are carried out.
It is operated by Cumbria Safety Cameras on behalf of Cumbria Police, part of the Cumbria Road Safety Partnership.
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 cameras and are continuing to speed."
In total, 5,569 motorists were caught, but only those who drove faster than 60mph - about 2,800 people - will be prosecuted because of limited resources.
They will each receive £60 fines, raising about £168,000 which will be passed to the Treasury, according to Mr Tea.
A Highways Agency spokesman said: "There's a 50mph speed limit, cones, barriers and signs in place on this stretch of the M6 for a very good reason - to ensure the ongoing safety of drivers and road workers while the work is underway.
"We are concerned about the number of drivers who appear to be ignoring the speed limit, putting themselves and our workforce in danger.
"Driving through half a mile of roadworks at 70mph takes just ten seconds fewer than driving at 50mph - a ten-second saving which can put lives at risk."
But Claire Armstrong, co-founder of Safe Speed - which campaigns against speed cameras - said: "We're pretty disgusted. It's obviously got nothing to do with road safety.
"The fact 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."
Ms Armstrong said traffic police officers are a much better judge of road safety as they assess a motorist's overall driving, not just their speed.
"You don't measure safe driving in miles per hour," she added.
The M6 roadworks are due to be completed by 26 March.