Claire Mercer said she may apply for a judicial review, as part of a campaign against the decision to convert traditional motorways into all lane running (ALR) smart motorways.

Ministers abandoned the smart motorways roll-out in April,claiming there is “a lack of confidence” following dozens of deaths, but said hard shoulders removed along more than 230 miles of carriageway will not be reinstated.

Ms Mercer’s husband Jason, 44, and Alexandru Murgeanu, 22, were hit by a lorry and killed on a stretch of M1 which did not have a hard shoulder, after they stopped to exchange insurance details following a collision near Sheffield, in June 2019.

At an inquest into the deaths, coroner David Urpeth said the motorways carried "an ongoing risk of future deaths".

Ms Mercer’s lawyers, who work for Irwin Mitchell, wrote to the Government and National Highways in October, urging them to reinstate hard shoulders on all smart motorways.

But have been told they will not receive a detailed response until April.

Lawyer Helen Smith said: “Too many lives are being turned upside down and families being torn apart because of collisions and deaths on smart motorways.

"Coroners, the Transport Select Committee, an independent road safety expert and even the Prime Minister have all also expressed real concerns about the safety of ALRs.

“Despite this, transport bosses and the Government continues to drag its heels on taking decisive action to reinstate the hard shoulder.”

National Highways has previously claimed smart motorways are the “safest roads” in the country and constantly monitored with a network of cameras and a stopped vehicle detection (SVD) system.

But that detection system has gone offline without warning 28 times since November 2021, according to figures obtained by a Freedom of Information request.

The longest unplanned SVD outage, between junctions 2 (Thorpe) and 4a (Fleet) on the M3 in September 2022, lasted 10 hours and 14 minutes.

Official figures show there were 495 deaths on motorways between 2015 and 2020 and 32 of those occurred on smart motorways with no hard shoulders.

National Highways Chief Executive, Nick Harris, said: “Safety is our highest priority and we are committed to further improving ALR motorways.

"We have completed key upgrades to improve the performance of technology to detect stopped vehicles, and today we have set out the next sections of motorway to benefit from the programme to install more than 150 extra emergency areas.”

A government spokeswoman said: “This was a tragic incident, and our thoughts continue to be with Jason’s family for their loss.

“The Government has already cancelled plans for all new smart motorway schemes, recognising public concerns. Working with National Highways, we are investing £900m in further safety improvements on existing smart motorways.”

Widow of man killed on smart motorway threatens legal action as she calls for reinstatement of hard shoulder