Work on a £373 million project to convert 23.6 miles of road into a four-lane highway with no hard shoulder is due for completion later this year or in early 2023.
But one lane will remain coned off after Department of Transport officials accepted recommendations to pause rollout of new all lane running schemes until more safety data is available.
Miles of smart motorway already open between MK and Hemel Hempstead and north of junction 16 in Northamptonshire will also be upgraded as part of a £900 million safety programme.
The move announced on Wednesday (January 12) comes just days after dashcam video of a scary near-miss on the same stretch of M1 where two men died in 2019.
Jason Mercer, 44, and 22-yerar-old Alexandru Murgeanu were hit by a lorry as they stopped in a live lane to swap details after a bump near Sheffield.
Jason's wife Claire has campaigned for smart motorways to be scrapped and has launched a legal bid for their use to be halted as she says accidents are common on the roads.
A terrifying recording, taken last Wednesday (January 5), shows a vehicle swerving at the last minute to avoid a stranded van with no warning signs visible.
Extra work to be carried out while the rollout is paused will include additional emergency refuge areas, so drivers have more places to escape speeding traffic if they break down, and Stopped Vehicle Detection systems.
Independent road safety campaigner, Meera Naran, whose eight-year-old son Dev, died in a motorway crash on the M6 in 2018, said: "I’m encouraged by the commitment of £900m to improve the safety of our motorways.
"However, I’ll continue to both challenge and work alongside the Department for Transport to ensure even more is done, including calling for legislation to be looked at for Autonomous Emergency Braking and further support for on-going driver education."
Transport Secretary Grant Shapps said he was looking to 'raise the bar' on road safety, adding: "While our initial data shows that smart motorways are among the safest roads in the UK, it’s crucial that we go further to ensure people feel safer using them.
“Pausing schemes yet to start construction and making multi-million-pound improvements to existing schemes will give drivers confidence and provide the data we need to inform our next steps."
A BBC Panorama investigation in 2020 revealed 38 people died on Britain’s 200 miles of smart motorways in the previous five years, compared to 90 a year over the whole 2,300-mile network.
Coroners have expressed concerns following deaths on stretches of the M1 already converted into smart motorways.
National Highways CEO Nick Harris said: “We have listened to public concerns about smart motorways and we are fully committed to taking forward the additional measures the Transport Committee has recommended.
“While we pause those all lane running schemes yet to start construction we will complete the schemes currently in construction, we will make existing sections as safe as they can possibly be and we will step up our advice to drivers so they have all the information they need.
“We are doing this because safety is our absolute priority and we want drivers to not just be safer, but also to feel safe on our busiest roads.”