Motorists across the UK could be fined and land several penalty points for making a simple error on a smart motorway
Smart motorways cover hundreds of miles across England and allow the hard shoulder to be used as an additional lane.
New research has found that millions of drivers could be making a simple mistake which could land them a £100 fine and three penalty points.
According to the research by the RAC more than a fifth of motorists have driven in a lane closed and marked with a red X sign over the past year.
Red Xs mark a lane on the motorway that has been closed and drivers must not drive on them as a result.
Twenty-three per cent of drivers surveyed admitted to breaking the rule, with 19 per cent doing so occasionally accidentally, while just three per cent break it on purpose.
Highways England has been working to improve driver compliance with the smart motorway red X and has issued
more than 160,000 warning letters to motorists.