Experts say we’ve taken a wrong turn on long-term road maintenance
Experts say Britain has taken a wrong turn on long-term road maintenance.
There are now more than one million potholes across the UK, roughly six for every mile of road, and the problem seems to be getting worse due to what experts say are the wrong methods being deployed to repair them.
In a bid to stop the rot, the government has committed £7.3 billion for roads over the next four years and is now pushing councils towards longer-term maintenance strategies rather than simply reacting once potholes appear.
Despite that shift, drivers returning from trips abroad still wonder why roads in countries such as Germany, France and the Netherlands often appear better maintained.
So why do Britain’s pothole repairs fail?
Nick Thom, assistant professor of civil engineering at the University of Nottingham, said some repairs are simply not designed to last.
“Pothole filling carried out in winter is usually done as a cheap emergency repair, without proper preparation of the surrounding surfaces and with materials that are not designed to last more than a few months,” he said.
According to Thom, short-term repairs often rely on cold asphalt mixtures because they can be applied in cold and wet conditions.
He also cited research from one of his PhD students, who found repairs made in winter were more likely to suffer major fretting, where stones begin coming away from the road surface.
Did Britain make the wrong choice?
However, Thom said winter repairs are only part of the problem.
He explained that around 25 years ago the UK began moving away from Hot Rolled Asphalt (HRA) in favour of so-called thin surface course systems.
Thom said the decision to move towards thin surface course systems, which was taken to reduce road noise and spray, “contributed a lot” to the pothole problems drivers experience today.
“The material was really designed for faster roads, like A-roads and motorways,” said Thom, “but around the same time many local authorities decided to follow the same approach on secondary roads. Where speeds are much lower, and spray not an issue, HRA would have been a much better solution. I would say we as a nation got it wrong.”
Thom said HRA often lasts more than 30 years, while some thinner surfacing systems last no more than 10 to 15 years before needing attention.
But Mike Hansford, who leads the Road Surface Treatments Association, said Britain’s pothole problems cannot be explained by thin layer surfacing materials alone.
He added: “It was almost like a perfect storm, because we introduced these thin surface course systems and at the same time stopped doing all the surface dressing on the scale we had been doing.”
Hansford said experienced engineers also left the industry at the same time, creating gaps in knowledge around surface treatments.
According to Hansford, thin surface course systems depend far more heavily on preventative treatments such as asphalt preservation or rejuvenation, surface dressing or microsurfacing, to protect and seal the road surface. But surface dressing, where roads are sealed using bitumen and stone chippings, has become less common.
He said: “It has been reduced from over 90 million square metres in 2008 to 35 million square metres in 2023 at its lowest. That has been a significant contributory factor to why we are where we are.”
Why do roads abroad seem better?
The Netherlands took a slightly different approach. Professor Bert van Wee from the Delft University of Technology said Dutch authorities began introducing quieter road surfaces in the 1980s despite knowing they would wear out more quickly than traditional materials.
“We still do it, because the benefits for road safety, visibility and noise are more important,” he explained.
“It’s a deliberate choice. It’s not that they forgot that they needed to replace those asphalt layers sooner than the traditional types of asphalt.”
Back in the UK, Malcolm Simms of the Asphalt Industry Alliance said preventative maintenance still has an important role to play, but he added that roads already in poor condition may first need more extensive work.
“In a lot of cases, the surface layer is only as good as what it is laid on,” he said.
“If you have a weak foundation and you put something relatively thin on top of it, you still don’t have the strength underneath.”
He also said the timing is critical: “While I wouldn’t say you would be wasting your time and money, you’re potentially compromising [the effectiveness of prevention) from day one by ‘protecting’ something that is already starting to fail.”
The Department for Transport has said councils carried out 15% more pothole prevention work last year and insists longer-term funding should improve repairs.
So when can drivers expect to see a noticeable improvement in our roads?
Hansford said: “There’s a longer-term and increased government funding commitment in place until 2029/2030. With the DfT encouraging the use of preventative treatments, by the end of that period, providing everyone uses the funding sensibly, think we will start to see an improvement in the network.”
Simms is more cautious. “There is an £18.62 billion backlog to fill in England and Wales,” he said.
“Authorities have told us that if the money was available it would still take around 12 years to complete the work, and that’s on top of existing road projects.”
Simms believes the improvements will take time. “You’re talking at least 10 years,” he added.
“But if the work was actually done to get to improved conditions), authorities tell us they could then reduce their budget demands by a billion pounds a year. So it’s 10 years of solid investment to get multiple years of future benefits.”
