The ex-minister who signed off Britain’s smart motorways has called for the rollout of the scheme to be halted immediately, and accused Highways England of killing motorists by “casually ignoring commitments” on safety systems.

Mike Penning, who was roads minister in 2010, spoke out as he and fellow MPs published a damning report on the motorways, which allow motorists to drive on the hard shoulder to increase capacity.

It said the admission by Highways England chief executive Jim O’Sullivan that radar technology could have saved lives was “a gross public policy failure and a damning indictment of the agency’s on-the-hoof approach”. The system has only been implemented on about 6% of the smart motorway network.

MPs said the Stopped Vehicle Detection system should have been in place from the outset, and said the agency’s commitment to the Commons transport committee in 2016 to adopt it for all subsequent schemes appeared to have been ignored.

The report, by the all-party parliamentary group on roadside rescue and recovery, described the recordings of 999 calls of motorists who had broken down in live lanes and were trapped in fast-moving traffic were “harrowing” and underscored that “many motorists don’t know what to do in such situations”.

The report found that the proportion of smart motorway breakdowns that came to a halt in lanes of moving traffic was almost twice that of normal motorways - 38% versus 20%.

Recovery vehicles, which are officially advised to “orbit” a breakdown until the lane is closed, were also being put in an “unacceptable position” with an average wait of 34 minutes until emergency services arrived, MPs found.

The report said that some recovery operators, “knowing that many such stranded motorists have been killed or seriously injured … choose to put their vehicle between the stranded motorist and the oncoming traffic. This impulse is understandable … however, it is completely unacceptable for them to be put in this position.”

The MPs called for emergency refuge areas to be built every 800m, rather than the average spacing of 2,500m, to improve safety. The distance would be similar to that in early trials on the M42 which convinced Penning to sign off the scheme.

Penning, who chairs the all-party group, said the report’s findings would be “of little succour to the families who are without loved ones today because of design faults in all lane running smart motorways”.

He said that the roll out had “been conducted with a shocking degree of carelessness – smart motorways today do not resemble the designs I signed off as roads minister. And Highways England appear to have casually ignored the commitments they made to the House of Commons in 2016. That is not acceptable.”

Penning called for the roll out of smart motorways to stop immediately, and for Highways England to implement changes to existing stretches “so that more tragedies can be avoided”.

The system is already under urgent review after it emerged that the death toll on stretches of smart motorways has reached 38 in the last five years – including some in accidents that motoring organisations believe were avoidable.

A BBC Panorama investigation found that the conversion of part of the M25 to all-lane running resulted in 20 times more dangerous near-misses.

The transport secretary, Grant Shapps, has asked officials to review evidence, and he told the BBC: “We absolutely have to have these as safe or safer as regular motorways or we shouldn’t have them at all.”

The RAC called for a commitment to install stopped vehicle detection technology across the network, and to build more refuge areas, citing research showing more than two-thirds of drivers believe safety was compromised on smart motorways. Head of roads policy Nicholas Lyes said: “It is now abundantly clear things need to change.”