This follows an announcement in March 2020 from the Transport Secretary Grant Shapps that all new smart motorways will be all-lane running schemes.
The Transport Committee claimed that "data on the safety and economic performance of existing all-lane running smart motorway schemes were insufficient to reach that judgment."
In a report published today (2 Nov), the cross-party group suggests the Government should explore alternative options for improving road capacity while it collects and evaluates data on existing all-lane running schemes.
Currently, only 29 miles of all-lane running motorways has five years of safety data available. The Committee has demanded that work on the roads should only resume when the same amount of data is available for the remaining 112 miles of all-lane running motorways introduced before 2020.
The 'Rollout and safety of smart motorways' report said: "The low number of incidents that occur on individual roads means that casualty data are often volatile, with rates fluctuating considerably from year to year.
"Such fluctuations make it difficult to establish whether differences in casualty rates between types of motorway are statistically significant."
"In conclusion, we are not convinced that the benefits of all-lane running motorways are sufficient to justify the risks to safety associated with permanently removing the hard shoulder."
Other recommendations include reducing the distance between emergency refuge areas on existing all-lane running motorways to 1 mile apart, decreasing to every 0.75 miles where possible. And adding an emergency corridor manoeuvre to the Highway Code, to help emergency services vehicles access incidents.
The Committee also suggested that the Department for Transport and National Highways should commission an independent evaluation of stopped vehicle technology.
Chair of the transport committee, Huw Merriman MP, said: "The Minister for Roads described England's all-lane-running Smart Motorways as 'the most scrutinised 141 miles of road in the world'. It is right we do so because lives have been lost and many motorists feel unsafe using them.
"Some 40% of breakdowns on all-lane-running motorways take place in live lanes. This is too high."
He added: "[Only] when enough time has been afforded to assess the safety of smart motorways over a longer period and when the Office of Rail and Road, as the independent road safety regulator, have been given powers to evaluate it, should we move to roll-out more miles of smart motorway."
RAC head of roads policy Nicholas Lyes said: "We welcome the Committee's report which once again raises many of the concerns about 'all lane running' motorways expressed by both drivers and the RAC.
"We feel a huge question mark remains over whether it's right that yet more money is spent on rolling out further all lane running smart motorways when there are clearly viable alternatives available. We'd like to see the Government take a second look at the benefits of dynamic hard shoulder schemes as a matter of urgency."
Read the full 'Rollout and safety of smart motorways' report.