More commonly found on A-roads and across sections of highway with roadworks, average speed cameras measure how long it takes a car to travel between two fixed points. By working out the average, they can then tell when a vehicle has been exceeding the stated limit. 

However, a survey of 3,000 people conducted for the RAC Report on Motoring found that 54 per cent of drivers would be in favour of using them on regular stretches of motorway in order to enforce the 70mph speed limit. 

It comes despite 56 per cent of respondents admitting to breaking the speed limit on motorways, with 34 per cent saying that they had travelled above 80mph. Three per cent even stated that they had exceeded 100mph. 

RAC road safety spokesman Simon Williams said: “Despite more than half of drivers admitting to regularly exceeding the 70mph speed limit, road safety statistics clearly show that motorways are our safest roads.

“With so many motorists admitting to driving much faster than they should on the motorway, it was interesting to see such strong support for average speed cameras to be used more widely to enforce the 70mph limit as opposed to just in roadworks, as is currently the case.

“We believe drivers see these cameras as being very effective at reducing speeds over longer distances and controlling traffic flow as well as being fairer than fixed position ones as they aren’t instantly punished for a momentary transgression.”

Speed limit compliance is higher on those roads with lower limits. However, the study revealed that 39 per cent of people ‘frequently disobeyed 20mph limits’ while 33 per cent admitted the same of 60mph country lanes.