Only 7% of Strategic Road Network Built to National Highways’ Climate Standards

Just 7% of England’s Strategic Road Network (SRN) has been upgraded to meet the climate resilience standards introduced by National Highways around two decades ago, according to figures revealed by New Civil Engineer.

Speaking at an event hosted by the Resilient Cities Network on 4 February, Angela Halliwell, National Highways’ head of carbon and air quality, said that although climate standards were updated many years ago, the vast majority of the network remains built to older specifications.

“We updated our standards so that they have a 20% rate of capacity for the kind of weather changes coming,” she said. “The challenge we’ve got is that 93% of our network is still to the previous standards.”

The SRN spans around 7,400km, meaning only approximately 518km currently meets National Highways’ modern climate adaptation requirements.

Funding and disruption limit upgrades

Halliwell acknowledged that upgrading the remaining network presents major challenges. She said financial constraints, carbon budgets and the impact on road users all limit how quickly adaptation can take place.

“We do not have the funding or the customer patience or the carbon budgets to dig up 93% of our network to replace it to the new standard,” she said.

She added that the issue is compounded by the age of the network, much of which was designed for very different traffic demands and climatic conditions.

“It was all built for a very different world and a very different climate,” Halliwell said, noting that the SRN is already under significant pressure from current traffic volumes.

Focus on high-risk areas

Rather than attempting wholesale upgrades, National Highways is prioritising the most vulnerable parts of the network. Halliwell said around 10% of the SRN lies in high flood-risk areas, which will be the focus of targeted interventions.

“We had about 1,800 flood events last year,” she said. “If we can’t upgrade all our drainage, we also look at wider interventions off the network.”

She described integrating climate resilience into routine asset management as the most cost-effective approach, allowing improvements to be delivered gradually over time.

Future restrictions possible

Halliwell warned that the pace of climate change could eventually force more fundamental changes in how the SRN is used.

“We can’t adapt at the pace at which climate change is here and present,” she said. “In the future, we may have to look at how the network is used differently, including proactively closing sections for safety.”

Her comments build on remarks made last year by Stephen Elderkin, National Highways’ director of environmental sustainability, who said the organisation must plan for “a wetter, hotter, windier future”.

Net zero and resilience commitments

National Highways has committed to reaching net zero across its operations by 2030, for construction and maintenance activities by 2040, and for the entire network by 2050.

A spokesperson said: “As with any long-established infrastructure network, much of our roads were built to the standards of their time. Our current design standards now include additional drainage capacity to account for the impact of climate change.

“We are taking a holistic approach to climate adaptation and resilience, including nature-based solutions such as peatland restoration through initiatives like Moors for the Future, which help reduce flooding risk while cutting carbon emissions and restoring habitats.”