Less than half (48%) of UK motorists know the rules for using smart motorways, a new survey suggests.
Just over one in four (27%) drivers say they are aware of what a smart motorway is but do not know the relevant regulations, according to the poll commissioned by road safety charity Brake and breakdown recovery firm Green Flag.
A further quarter (25%) of the 2,010 drivers questioned said they do not even know what a smart motorway is, let alone what the rules are.
Smart motorway rules include not driving in lanes below a red X.
Drivers are also urged to use refuge areas when possible if they suffer an emergency or breakdown, rather than stopping in live lanes.
Smart motorways are used to increase capacity without the more disruptive and costly process of widening carriageways.
They feature various methods to manage the flow of traffic, including variable speed limits and using the hard shoulder as a live running lane.
Once Highways England is alerted to a stopped vehicle in a live lane, overhead gantries will display a red X to indicate the lane is closed.
But there are concerns it can take too long to spot a stranded vehicle and that some drivers ignore red Xs.
BBC Panorama found at least 38 people have died on stretches of smart motorways in the past five years.
A lorry driver was jailed for 10 months last week for causing the deaths of two men in a collision on a stretch of smart motorway.
Jason Mercer, 44, and Alexandru Murgeanu, 22, died when a lorry driven by Prezemyslaw Szuba, 40, ploughed into their stationary vehicles on the M1 near Sheffield on June 7 last year.
An “evidence stocktake” published by Transport Secretary Grant Shapps in March stated the risk of a collision between moving vehicles is lower on smart motorways than conventional motorways but the chance of a crash involving a moving vehicle and a stationary vehicle is higher when the hard shoulder is removed.
It led to an 18-point action plan that included installing more places to stop in an emergency and faster roll-out of a radar-based system to detect broken-down vehicles.
Highways England insists smart motorways are “at least as safe as, or safer than, the conventional motorways they replaced”.
The smart motorway network covers around 500 miles in England, with an additional 300 miles planned by 2025.
Brake director of campaigns Joshua Harris said: “Drivers are confused about the rules of driving on smart motorways and communication efforts must urgently be stepped up to help avoid more tragic incidents on these roads.
“We welcome the measures the Government has outlined to improve smart motorway safety and urge them to follow this evidence-led approach for all UK roads.
“With more than 75 deaths and serious injuries on our roads every day, improving road safety must be a priority for this Government.”
Green Flag head of service delivery Damon Jowett said: “While the smart motorways system allows for drivers to get to their destination more easily, understanding of the rules is paramount to ensure road safety.
“Our latest report has highlighted concerning gaps in driver awareness.”
Steve Gooding, director of the RAC Foundation, said: “Mile for mile, motorways are our safest roads, but they could be safer still.
“Ministers have promised to close the knowledge gap through better information campaigns. These numbers reveal how big that gap actually is.”
A Highways England spokesman said: “We are committed to making journeys on our roads safer and better for everybody and in the new year we’ll launch our latest campaign to increase awareness and understanding, particularly around what to do in the event of a breakdown.
“Meanwhile we welcome any research which together with our own insight help us understand what road users think and can help inform future road safety campaigns.”