Sir Mike Penning, the coalition government’s roads minister, signed off a £2 billion smart motorways project in 2013, but has always insisted he was unaware Highways England would fit those emergency areas 1.5 miles apart, instead of every third of a mile, as in the M42 trial. Last year, the smart motorway death toll reached 38.

Meera Naran called for a review after her eight-year-old son, Dev, was killed in 2018 on a “dynamic” stretch of the M6 where the hard shoulder can be turned on and off. Just months earlier, Jamil Ahmed, 36, died in near similar circumstances at the same spot, prompting his wife, Badra, to forewarn of yet another tragedy.

It is thought that motorists may have been confused about when the hard shoulder was open or closed to them. Public awareness about the transformation of our road network has been low, with many motorists only learning about the different types of smart motorways through media coverage of those who have died.

However, Mrs Mercer’s high-profile campaigning about the dangers of smart motorways encouraged National Highways to launch its first television advertisement last year, at a cost of £5 million, which urged people to pull in and get over the barrier if their car fails to reach a refuge area. This was accused of being in bad taste as the commercial featured two fly-characters squashed against windscreen, singing “Go left!” to the Pet Shop Boys hit.

Mrs Mercer even decided to publish advice in foreign languages after realising lorry drivers, often from Eastern Europe, were involved in a number of crashes because they may not have known they could encounter stranded vehicles.

In the years since the 2006 trial, the technology used on smart motorways has repeatedly been found wanting. Documents obtained through Freedom of Information laws by this newspaper showed that the road signalling systems meant to close lanes with a red “X” have been stricken by bugs. A National Highways whistleblower revealed one piece of software had been nicknamed “Die Now” because it became unusable three times in four days, disabling signals covering huge swathes of the M1, M4, M5 and M63.