Claire Mercer accused the Department for Transport of “stalling tactics” and demonstrating a “lack of common decency”.
Her husband Jason, 44, died when he was hit by a lorry after stopping on the M1 near Sheffield in 2019.
Law firm Irwin Mitchell, representing his family, said it wrote to the Government and National Highways in October outlining “compelling evidence regarding safety concerns”.
It pushed for hard shoulders to be reinstated on smart motorways where emergency lanes have been converted to live lanes to boost capacity.
The firm said it took more than eight weeks to get a reply and was told a final response would be given by the end of April.
Claire said: “We’ve spent four years providing evidence of how unsafe all-lane running smart motorways are.
“They have been aware of the safety concerns throughout so their continued delays in taking action will result in more peoples’ lives being put at risk. I won’t rest until the hard shoulder has been returned.
“The Government and National Highways need to pull their fingers out and treat this request with the seriousness it deserves.”
Last April Prime Minister Rishi Sunak cancelled projects to build all-lane running smart motorways due to cost pressures and a lack of confidence among road users.
But he has refused to reinstate the hard shoulder on existing smart motorways. Helen Smith, smart motorways lawyer at Irwin Mitchell, said: “Transport bosses and the Government continue to drag their heels on taking decisive action to reinstate the hard shoulder and to prioritise the safety of road users.”
A National Highways report published last month revealed that smart motorways without a hard shoulder are three times more dangerous to break down on than controlled smart motorways. These have variable speed limits but retain a hard shoulder.
