They were introduced to ease congestion around Birmingham, but there are claims tonight that the growing number of speed controls on motorways are causing confusion to drivers - and have become a distracting danger.
But the claims are strongly disputed. The Highways Agency say there's evidence that variable speed limits have brought a dramatic fall in accidents. Watch the full report.
The Highways Agency have told ITV Central they have "no idea" why a top motoring lawyer would claim that managed-motorways are unsafe.
Mr Loophole, as he's known, has criticised the use of variable speed limits on managed motorways has suggested that actually increasing speed limits would be safer for drivers.
We have no idea why such a claim would be made when a three-year safety report into M42 managed motorway scheme showed that since the scheme's opening in 2005 the total number of accidents reduced by 55.7 per cent and the severity of those that did occur also reduced with no fatalities reported. And, the system continues to perform well, not just on the M42 but also on stretches of the M1, M25, M6 and M62.
"Furthermore when we have spoken to people who use sections of managed motorway around Birmingham, they have said they welcome anything that makes their journeys easier and safer."
The Highways Agency say "managed motorways" have been working well for some time on the M42 and M6 near Birmingham.
A "managed motorway" uses overhead signage to control speed limits and hard-shoulder running, depending on the level of congestion, to make journey times more reliable.
The Highways Agency website says: "We introduce managed motorways where it is the best solution to tackle congestion. We use the most appropriate methods and technology to ensure people can make their journeys reliably and safely."
Work is currently taking place on the M6 around Spaghetti Junction to implement the managed motorway system.
A top motoring lawyer has criticised variable speed limits on motorways, saying they are confusing and a danger to drivers.
Nick Freeman, aka Mr Loophole, says having different speeds for different lanes can be a hazard because "motorists are more concerned about not going over the limit flashing on the gantry ahead of them instead of keeping a careful eye on the road in front of them."
Mr Loophole cited the M42 near the NEC as one example.