Potholes are a safety risk, source of vehicle damage and recurring annoyance in the UK. They gain special visibility at times of local elections, given that the vast majority of roads are maintained by local authorities. A survey conducted in April found that road condition was the top local issue for voters throughout Britain ahead of the May 7 elections.
The Asphalt Industry Alliance’s (AIA) 2025 report indicates that 17% of the local road network in England and Wales is in poor condition. It estimates that the backlog of repairs would take a staggering 12 years to clear, costing £16.81 billion.
While it’s easy for politicians to point to numbers of potholes filled as a way to gain votes from frustrated drivers, this does nothing to solve the problem in the long run.
Where do potholes come from?
Potholes are not isolated road surface defects, but rather the end-product of a hidden road deterioration process. In typical asphalt roads, bitumen ages, stiffens and becomes brittle over time. Traffic passage causes the road surface to crack.
Once cracks form, water enters the road structure. The weight of vehicles and freeze-thaw cycles over winter cause these cracks to expand and widen, eventually resulting in a pothole. By the time it appears on the road surface, the structural integrity of the subsurface is already compromised.
In the wake of climate change, the UK’s increasingly wet winters accelerate this process, especially on roads that have reached the end of their structural life.
The UK’s approach to repairing potholes is largely reactive: a short-term, localised patch job after the road has failed. Experimental studies show that while this approach is relatively inexpensive per intervention, it suffers from severe underperformance.
These repair jobs often last for just weeks or months in wet or winter conditions before needing to be done again. This “patch and repeat” cycle leads to escalating costs, network disruption and inconsistent road quality.
A much better approach would be preventative maintenance – intervening before failure occurs. Preventative treatments, including surface dressing and crack sealing, yield superior cost-effectiveness because they substantially reduce the frequency of patch failure and replacement.
It’s important to note that filling potholes, in itself, does not add life to roads, apart from temporarily keeping them safe. It is the construction equivalent of throwing good money after bad.
More ambitious would be to establish a predictive and proactive road management system that spans the road’s entire lifecycle. This includes designing and constructing resilient road structures, conducting frequent monitoring, and applying targeted, timely preventive maintenance.
Emerging technology such as advances in data analytics, AI, automation, digital twins and non-destructive testing may make this approach increasingly feasible.
Economics of potholes
Evidence suggests that preventative maintenance would be longer lasting, and significantly more cost-efficient. Spending £1 today on preventative maintenance leads to £4.20 saved within 10 years.
This payback reflects the current poor condition of the local road network in Britain. More sustainable road maintenance would have a rapid effect.
Similar evidence exists for the climate impact. Traditionally, potholes are fixed again and again using cold-mix or hot-mix asphalt – a mixture of stones and petroleum-based bitumen derived from crude oil. This makes the process incredibly carbon-intensive.
Preventative maintenance reduces the long-term carbon costs because roads stay in good condition for longer. As extreme weather such as floods or heatwaves becomes more frequent, the risk of damage to road surfaces increases, making resilience a crucial factor in highway maintenance.
Put another way, preventative road maintenance could be a key part of local authority’s net zero ambitions – whereas the current approach is a liability to this goal.
The electoral focus on fixing potholes therefore seems odd, since the medium- to long-term solution (from a cost, road quality and carbon perspective) is more preventative maintenance.
Preventative maintenance is a cost-effective alternative to the UK’s ‘patch and repeat’ approach. Daz Hopper Photography/Shutterstock
Why are Britain’s roads so pothole-plagued?
The simple reason that local authorities can’t fix potholes permanently is a lack of funding. However, like many political issues, it is more nuanced.
Our work with the National Highways & Transport Network has found that the public’s satisfaction with roads is substantially driven by the condition of roads within a one-kilometre radius of where they live.
Politically, potholes are obviously visible – they are also classed as safety defects, so there are legal requirements for local authorities to “fix” them in a timely manner. But underlying road condition, while crucial to the emergence of potholes, is more hidden and does not get as much political bandwidth.
Local authorities receive various funding pots for road maintenance, but this funding can sometimes be reallocated to other authority services, such as adult social care. This seriously constrains funding that is spent on road maintenance, although the UK government has recently announced new rules to stop councils from diverting road maintenance funds.
Taken together, this means that preventative maintenance is crowded out by limited funds and the need to repeatedly fix holes that result from a lack of preventative maintenance.
A review of current local road maintenance budget allocations reveals that reactive maintenance consumes 25% of budgets. But the pothole problem is getting worse, which suggests this figure will rise over time.
The relatively recent extra money for road maintenance (£0.5 billion annually) allocated could help, but it won’t go very far unless put into preventative treatments.
Changing to a longer-term solution requires different approaches to government funding and policymaking. But this demands political will at all levels of government, at a time when local authority budgets are already very constrained.
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