Questions raised over National Highways' commitment to safer motorway barriers

Concerns are growing over whether National Highways is doing enough to improve motorway safety after figures revealed limited progress in replacing ageing steel central reservation barriers with modern concrete alternatives.

Parliamentary responses have shown that just 53km of life-expired steel barrier has been replaced with concrete systems between 2020 and 2025, despite National Highways identifying around 1,620km of steel barrier requiring renewal in its own 2022 improvement strategy.

The figures have prompted criticism from industry experts, who argue that the pace of replacement falls well short of what is needed to improve safety across the strategic road network.

The Department for Transport has recommended since 2005 that high-containment concrete barriers should be the preferred option when replacing life-expired steel barriers on heavily trafficked motorways carrying more than 25,000 vehicles a day. Yet several recent schemes have reportedly seen steel barriers installed instead.

Locations where steel-for-steel replacements have been approved include sections of the A1(M), M4, M5 and M6, raising questions about why concrete systems are not being used more widely despite long-standing government guidance.

The issue has become increasingly relevant as vehicle weights continue to rise. Industry representatives point out that many existing steel barriers were originally tested against vehicles weighing around 1.5 tonnes, whereas modern electric cars frequently weigh between 1.8 and 2.2 tonnes due to their battery packs.

Britpave, the infrastructure and concrete paving association, has questioned whether short-term budget pressures are influencing decisions at the expense of longer-term safety and performance benefits.

Chair Al McDermid said the organisation was concerned that National Highways may be prioritising upfront cost savings over infrastructure capable of dealing with today's heavier vehicle fleet.

“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,” he said.

Concrete barriers are designed to contain a wider range of vehicles, including SUVs, vans, coaches and heavy goods vehicles, while also requiring less maintenance over their operational life. Supporters argue this not only improves safety but also reduces traffic disruption and long-term carbon emissions associated with maintenance activities.

McDermid added:

“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.”

With only a small fraction of the identified replacement programme completed, questions remain over whether National Highways is moving quickly enough to modernise safety infrastructure on some of the country's busiest roads.

As traffic volumes increase and vehicle technology evolves, critics argue that a clearer strategy is needed to explain why many ageing steel barriers remain in place and why concrete alternatives are not being adopted more consistently across the motorway network.