Parliamentary answers have revealed National Highways has replaced just 53km of life-expired steel central reserve barrier with concrete between 2020 and 2025.

That is despite its own 2022 improvement plan identifying around 1,620km of steel barrier needing replacement across the network.

The Department for Transport mandated in 2005 that stronger H1 concrete barrier should be the default option when life-expired motorway steel barrier is replaced on roads carrying more than 25,000 vehicles a day.

But a parliamentary questions tabled by Shadow Transport Secretary Richard Holden has revealed departures from the standard on several schemes.

Projects where steel has been approved instead of concrete include sections of the A1(M) J37-38, M5 J23-24, M6 J37-38 and M4 J13-14. A further steel-for-steel replacement has also been reported on the A1(M) J61-62.

Concrete trade body Britpave said the answers raised serious questions over National Highways’ long-term commitment to improving safety on the strategic road network.

It warned the issue is becoming more urgent as heavier electric cars and commercial vehicles increase the risk of crossover accidents.

Britpave chair Al McDermid said it was concerned that National Highways may be putting short-term costs savings before a safer road network with better whole-life cost and reduced carbon benefits.

He said: “These concerns are amplified when you consider the growing number of heavier vehicles including heavy electric cars using the network. The programme to replace steel motorway barriers with concrete should be accelerated to negate the potential of crossover accidents.”

Britpave said existing steel barriers were tested around 1.5-tonne cars, while many electric vehicles now weigh between 1.8 and 2.2 tonnes because of battery packs.

Rigid concrete barriers can contain 4x4s, light vans, buses, coaches and lorries up to 13.5 tonnes.

McDermid said: “Rigid concrete barriers offer unrivalled strength, safety and whole life performance and operational carbon reduction benefits. Despite these benefits being recognised by the Department for Transport and National Highways the programme for steel barrier replacement with rigid concrete barrier is being compromised by short-term cost misjudgements.”