The families of two people who died on a stretch of the M1 in South Yorkshire have jointly called for an end to the use of smart motorways.
Jason Mercer and Nargis Begum were killed in separate crashes after they stopped their vehicles where the motorway does not have a hard shoulder.
Their families say they are considering legal action against Highways England.
A review has found smart motorways are as safe as, or safer than, conventional motorways, Highways England has said.
Mr Mercer, 47, died alongside Alexandru Murgeanu, 22, from Mansfield, on 7 June 2019.
The pair had stopped after a minor collision near junction 34 of the M1 near Meadowhall when they were hit by a lorry.
In October, Prezemyslaw Szuba, of Adelaide Street, Hull, was jailed for 10 months after admitting causing death by driving without due care and attention.
Since Mr Mercer's death, his widow Claire, of Broom, Rotherham, has campaigned against smart motorways and is now appealing for other bereaved families to contact her.
She has instructed lawyers at Irwin Mitchell to investigate the case.
Mrs Begum died in September 2018 after the car she was a passenger in broke down near Woodall services.
She and husband Mohammed Bashir, 67, who was driving, got out of their vehicle and were waiting for help to arrive when another vehicle collided with theirs, causing it to hit Mrs Begum.
Her daughter Saima said: "They may be called smart, but they're anything but."
Helen Smith, of Irwin Mitchell, said: "Claire and Nargis's family are steadfast in their belief that smart motorways cost lives.
"We are continuing to uncover more information about smart motorways which backs up that view."