An investigation into the safety of smart motorways has been launched after concerns they could lead to further deaths.
Smart motorways often involve converting the hard shoulder to a live running lane to boost capacity without widening the carriageway.
They have been in the spotlight in recent weeks due to growing safety worries.
A coroner in Sheffield said smart motorways "present an ongoing risk of future deaths".
It comes after South Yorkshire Police said it wants to review files about Jason Mercer and Alexandru Murgeanu, who died on a stretch of the M1 with no hard shoulder in 2019.
Mr Mercer, 44, and Mr Murgeanu, 22, died when lorry driver Prezemyslaw Szuba crashed into their vehicles on the M1 near Sheffield in 2019.Another serious crash which happened this month, led to the South Yorkshire Police and Crime Commissioner calling for an urgent rethink.
Transport Secretary Grant Shapps told the committee earlier this month that he "inherited" smart motorways, and pledged to get "get rid of confusions".
These include "insane" dynamic hard shoulders, which switch between being used for emergencies and live traffic depending on demand.
He published a smart motorways action plan with 18 measures to boost safety.
Rotherham MP Sarah Champion has been leading calls for an end to smart motorways since her constituent Jason Mercer's death.
She has welcomed the new inquiry, saying "I have really high hopes that this will put such pressure on the government that they have to see common sense now and act."
She added: "When I talk to anyone, whether it's MPs, or constituents, or my mum, everyone is incredulous that motorways can exist without a hard shoulder. It makes no sense whatsoever
"When I first started raising this with Grant Shapps, he too said 'I know that there's a problem.'
"What we haven't seen is any desire to actually rectify that problem and save lives."
But Jason Mercer's wife, Claire, says she's concerned the inquiry will be biased towards keeping smart motorways.
She said: "If you look at some of the comments it already seems favourable to keeping smart motorways but adapting them.
"And that's not what's needed, we just need the hard shoulder back."
Tory MP Huw Merriman, who chairs the committee, said: "The Department for Transport says smart motorways help us cope with a 23% rise in traffic since 2000, helping congestion.
"The department's own stocktake report points to lower fatal casualty rates for smart motorways without a permanent hard shoulder than on motorways with a hard shoulder. The serious casualty rate is slightly higher.
"This message isn't reaching the public, whose confidence in smart motorways has been dented by increasing fatalities on these roads.
"Road safety charities are also expressing concerns. Will enhanced safety measures help? Will the public accept them following an awareness campaign? Or should there be a rethink of Government policy?
"There are genuine worries about this element of the motorway network and we want to investigate how we got to this point."
Labour's shadow transport secretary Jim McMahon said: "Dozens of people have lost their lives on smart motorways, so this investigation is welcome."
RAC head of roads policy Nicholas Lyes said: "There is an increasing level of concern around the safety of smart motorways from the driving public through to Westminster.
While a major review has identified a number of key actions to improve safety and some progress has been made, there is still a great deal of work to do which will take several years to complete
A Department for Transport spokeswoman said: "Since taking office, the current Secretary of State has expressed his concerns over smart motorways and has committed #500 million to safety improvements.
"We welcome this important inquiry from the Transport Committee and we will provide written evidence to help it in its work."