Smart motorways with a hard shoulder only used at busy times are "too complicated for people to use", the boss of Highways England has admitted.
Chief executive Jim O'Sullivan told MPs that it will not build any more "dynamic" smart motorways because too many motorists do not understand them.
The design is already in use on parts of the M1, M4, M5, M6, M42 and M62.
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Jason Mercer, aged 44, from Broom, Rotherham, and Alexandru Murgeanu, aged 22, from Mansfield, died in June when they were hit by a lorry after pulling over following a collision on the northbound M1 between Junction 34 for Meadowhall and 35 for Thorpe Hesley.
Mr Mercer and Mr Murgeanu were among four people to die on the same 16-mile stretch of the M1 within 10 months.
Mr O'Sullivan said drivers are confused about when they can use the hard shoulder and when it is closed to non-emergency traffic.
He explained to the Commons' Transport Select Committee that some hard shoulders on dynamic smart motorways are only open to running traffic during the morning and evening peaks, but this catches out some drivers when their routine changes.
"People whose normal daily commute takes place at 8am or 9am, if they've been to the dentist and come out at 11am they drive down the hard shoulder," he said.
"When we close it at other times of the day, people still drive down it."
Mr O'Sullivan said there is confusion over when the hard shoulder is and is not open to traffic.
"We get people who stop there when it's a running lane," he told the committee.
"What we also find is because people aren't sure if it's a hard shoulder or a running lane, even when it is open, the usage of that running lane is much lower because people aren't sure whether it's a hard shoulder or not."
He added: "I don't think we will be building any more dynamic hard shoulder smart motorways. They're just too complicated for people to use."
Other types of smart motorways include all lane running schemes where lane one - formerly the hard shoulder - is only closed in the event of an accident, and controlled motorways which have variable speed limits but retain the hard shoulder for emergencies.
Smart motorways have been developed as a way of increasing capacity and reducing congestion without the more costly process of widening roads.
There are growing concerns that the removal of a permanent hard shoulder has created a safety hazard, with some drivers being killed after stopping in live running lanes.
In March, Derek Jacobs, 83, was killed when his car was hit after it stopped in the fast lane on a section of the M1 in Derbyshire converted to a smart motorway.
This reportedly came months after a woman was killed on the same stretch of road after leaving a broken down car.
But Mr O'Sullivan insisted that smart motorways are "as safe or safer than conventional motorways".
He added: "I would prefer to break down in the live lane of a managed motorway or a smart motorway than I would prefer to break down on a live lane on a conventional motorway or on a dual carriageway."
Steve Gooding, director of motoring research charity the RAC Foundation, told the PA news agency: "The rules, regulations and layouts of roads should be easy to comprehend whether people are driving along them at 70mph or 7mph.
"The simpler motorways are to understand the safer they will be, as motorists concentrate on the hazards ahead rather than grappling with which lanes are available to them and which are not."