Question marks about the safety of smart motorways still remain following Highways England research.
While delivering less congested, more reliable journeys for drivers, red lane closure warnings are an issue.
The Highways England study into two stretches of the M25 which have traffic running on the hard shoulder found that up to 7% of drivers do not comply with red lane closure warnings.
Meanwhile, up to 85% of stops in emergency refuge areas are for non-emergencies. Just 4% of stops by HGVs were for actual emergencies.
"The results of these initial reports suggest that motorists are still getting to grips with how to make proper use of motorways with all-lanes running ('ALR'). This is consistent with our own research on this subject," says RAC chief engineer David Bizley.
"Non-compliance with red 'X's on ALR stretches of motorway is a particular cause for concern. With no permanent hard shoulder, the safety of someone breaking down in lane one is highly dependent on motorists obeying overhead signage indicating the closure of a lane to traffic.
"The misuse of Emergency Refuge Areas (ERAs) is also worrying. With spacing of ERAs further apart than on earlier designs of smart motorway and in the absence of a hard shoulder it is essential that ERAs are used only by those road users that are faced with a genuine emergency."
Smart motorways use active traffic management techniques to increase capacity by using variable speed limits and the hard shoulder at busy times.
On the two stretches of the M25 - between Junctions 23-27 and Junctions 5-7 - the hard shoulder is permanently converted for traffic.
The first year evaluation of the scheme found the accident rate has fallen, but Highways England says it is too early to make a "conclusive" analysis.
"It is encouraging that initial evidence suggests the safety performance of ALR to be no worse than a conventional motorway with a hard shoulder and indeed may be slightly better, but by Highways England's own admission, a further two years data will be needed before there is sufficient evidence to be confident in this conclusion," adds Mr Bizley.
Copyright Press Association 2016. Motoring News articles do not reflect the RAC's views unless clearly stated.