Smart motorway safety is back in the spotlight as a widow is calling for Highways England to be investigated over the death of her husband.

Here the PA news agency answers 14 key questions about the roads.

– What are smart motorways?

They involve various methods to manage the flow of traffic, including variable speed limits and using the hard shoulder as a live running lane.

– How many are there?

Motorways with sections where the hard shoulder has been removed include the M1, M4, M5, M6, M25 and M62.

This covers around 500 miles, with an additional 300 miles planned by 2025.

– What are the benefits?

They are designed to increase capacity without the more disruptive and costly process of widening carriageways.

– Why are there safety concerns?

Concerns have been raised about incidents where vehicles stopped in traffic and were hit from behind.

– What is the safety record of smart motorways?

Fourteen people were killed in 2019 on motorways where the hard shoulder was permanently removed or was temporarily used as a live running lane, according to Sunday Times analysis.

Jason Mercer, 44, and Alexandru Murgeanu, 22, died on the M1 in South Yorkshire in June of that year after a lorry ploughed into their stationary vehicles.

– What action is Mr Mercer’s wife taking?

Claire Mercer is demanding that Highways England is investigated over her husband’s death.

The organisation has already been referred by a coroner to the Crown Prosecution Service to consider if corporate manslaughter charges are appropriate in relation to the death of Nargis Begum, 62, on another smart motorway stretch of the M1 in South Yorkshire.

– What does the Government say about smart motorways?

An “evidence stocktake” published by Transport Secretary Grant Shapps in March 2020 said that “in most ways” they were as safe or safer than conventional motorways, but the chance of a crash involving a moving vehicle and a stationary vehicle was higher when the hard shoulder was removed.

– What was the result of this report?

An 18-point action plan included installing more places to stop in an emergency and faster rollout of a radar-based system to detect broken-down vehicles.

– What happens if I break down on a smart motorway without a hard shoulder?

Drivers are advised to pull into an emergency refuge area (ERA) if possible.

There are around 500 miles of smart motorways in England (Martin Rickett/PA)
There are around 500 miles of smart motorways in England (Martin Rickett/PA)

– How frequent are they?

They were initially up to 2.5km (1.6 miles) apart, but for new smart motorways built from 2020 they are no more than 1.6km (one mile) apart.

– What if I cannot reach an ERA or leave my vehicle safely?

If you come to a standstill in a live lane, call 999, switch on your hazard warning lights and stay in your vehicle with your seat belt on.

– What happens next?

Once Highways England is alerted to a stopped vehicle in a live lane, overhead gantries will display a red X to indicate the lane is closed.

– Are smart motorways used in other European countries?

The vast majority of motorway-style roads in Europe have a permanent emergency lane.

– What do drivers think about them?

An AA poll of 15,000 motorists suggested only one in 10 drivers felt safer on smart motorways without a hard shoulder than traditional motorways.