England's so-called smart motorways have been given new radar technology to detect broken down vehicles as part of an effort to fill all lanes of the country's technology-enhanced roads with traffic at the same time.

While most motorways around the world leave a hard shoulder empty so that cars can safely stop in the event of a breakdown or accident, smart motorways use various methods to manage the flow of traffic, including using the hard shoulder as a live running lane.

These motorways, introduced in England in 2014 as a cheaper way of increasing capacity compared with widening carriageways, also use variable speed limits to reduce travel times where possible.

There are about 600km of smart motorway in England, including 375km without a hard shoulder.

However, England's smart motorways also sparked safety fears following incidents of people being killed when being hit from behind while stopped in live traffic lanes.

British Transport Secretary Grant Shapps since announced in April that 111 more miles (179km) of radar tech has been added in the past year.

National Highways has committed to ensuring every stretch of motorway where the hard shoulder has been permanently removed, will have radar technology fitted by the end of September.

Shapps said National Highways will soon publish new data showing the roads "remain among the safest in the country, notwithstanding the concerns that we all have."

In January, the Department for Transport halted the development of new smart motorways without a hard shoulder until five years of safety data has been collected for schemes introduced before 2020.

This follows a report by the Transport Select Committee in November 2021 which said there was not enough information to justify continuing with new projects.

 - dpa