Ministers halted the rollout of 120 miles of smart motorway last night as safety fears about the 'death trap' roads continued to grow.
Transport Secretary Grant Shapps also said £390million would be spent on building 150 extra emergency laybys so drivers whose vehicles have broken down don't have to stop in live traffic.
It will boost the number of laybys on smart motorways by about 50 per cent and mean they are no more than a mile apart.
Currently they are up to 1.5 miles apart, which motoring groups warn is unsafe.
The development is a victory for the Daily Mail, which has campaigned for better safety on the controversial roads.
It came after a damning report by the Commons transport committee last year called on ministers to act over deadly flaws.
Campaigner: Claire Mercer's husband died on a live lane
Mr Shapps said he was adopting the report's recommendations in full.
But despite halting the construction of 120 miles of 'all-lane-running' (ALR) smart motorway – in which the hard shoulder is replaced with a lane in permanent use, a further 100 miles will go ahead because these stretches are more than 50 per cent complete and it was deemed safer to finish them.
The 120 miles will be paused until April 2024 so five years of safety data can be collected from more than 200 miles of schemes before a decision is made on whether it is safe to roll out new ALR roads.
The delayed schemes are made up of stretches totalling 60 miles on each carriageway.
Mr Shapps also agreed to consider letting the Office of Rail and Road sign off all new roads on health and safety grounds. The watchdog will also review radar technology meant to detect vehicles marooned in live lanes within 20 seconds. Officials claim it isn't effective.
He will also re-evaluate dynamic hard shoulder and controlled motorways. The former have a hard shoulder used as a live line intermittently, while the latter retain a hard shoulder but use variable speed limits.
AA president Edmund King said: 'At last we have a Transport Secretary who has taken a positive and pragmatic approach.' But he added: 'The AA view remains that controlled motorways with a hard shoulder are the safest option.'
The delayed schemes are made up of stretches totalling 60 miles on each carriageway
Nicholas Lyes, RAC head of roads policy, said the decision was 'an unqualified victory for drivers'.
Claire Mercer, who blames smart motorways for her husband's death, hailed it as a positive move, but said all motorways should have a hard shoulder.
Her husband Jason, 44, died in June 2019 when a lorry hit him on the M1 where the hard shoulder had been turned into a live lane.
Mr Mercer and delivery driver Alexandru Murgeanu, 22, were involved in a shunt, and were struck and killed when they stopped to exchange details.
Mrs Mercer, 45, said: 'The undercover report the Daily Mail did was a massive stepping stone
