Potholes are such a ubiquitous presence on the country’s roads that the humble crack in the highway was this year granted its first commemorative ‘day’. After seasons of extreme weather and tightening local repair budgets, the issue of road craters is undoubtedly one of national concern and now looks set to become a central fighting-ground for May’s General Election.
While the Department for Transport (DfT) has allocated £6bn to councils for repairing potholes and making local improvements, town halls and contractors still have a significant challenge ahead. Around a third of local roads are currently thought to be in urgent need of repair, with some councils facing a regional repair backlog worth up to £100m.
Caught in the middle of this dispute are the country’s motorists. Their frustration reached fever pitch in January with the launch of the UK’s first National Pothole Day, when drivers were encouraged to take to social media and publish photos of crater damage caused to cars. With even transport minister Patrick McLoughlin branding potholes ‘the bane of all our lives’, a solution to this crisis has become a national priority.
Yet Howard Robinson, chief executive of the Road Surface Treatments Association, says the country is still ‘missing a trick’ by failing to prevent potholes forming in the first place.
‘Potholes primarily form because water - particularly during the winter months - can penetrate into the asphalt road surface and then it freezes. As water freezes, it expands and cracks the asphalt. So what we should be doing is more sealing of the road surface. There is a lot of sealing that goes on. The main process is called surface dressing, which is undertaken across the UK by many authorities. But we can do far more,’ Mr Robinson says.
‘It’s now becoming more established,’ he adds. ‘Those authorities that are investing in surface dressing are seeing far fewer potholes.’
The four most commonly used methods to combat potholes in the UK are recognised to be hot mixed asphalt, cold mix asphalt, thermal road repairs and spray injection patching. Mr Robinson says a key reason for repairs failing prematurely is because the contractor ‘is trying to compact asphalt into a small area – and it’s quite difficult to do that’.
‘Asphalt is normally installed with a paving machine and compacted by rollers. So asphalt roads are norm very well compacted. When the contractor comes to repair potholes he is unable to compact that small area to the same degree of compaction. So the pothole repair is more porous, water can get into it and cause it to fail prematurely.’
He says cold mix asphalt is ‘growing in popularity’ and describes thermal road repairs as a ‘very good technique’ - even if it is only deployed by a single company in the UK, as Surveyor understands. Mr Robsinson says there is evidence spray injection patching can last up to two years but ‘if a road is then to be surface dressed, it becomes a permanent repair’.
While the country already seals around 75m square metres of road surface every year, Mr Robinson says even more can be done on local roads if greater funding is allocated and longer-term planning adopted.
‘If the local authorities make the money available and plan the works at least a year in advance, then the supply side can gear up to meet that need,’ he says. ‘Filling a pothole on average costs about £54 per square metre, but you can surface dress for £2 per square metre. If it’s done properly that sealing will last 10 years. It’s an excellent way for local authorities to preserve their biggest asset: their roads.’
Most town halls are upping their game to maintain local routes yet most must address a vast number of repairs. For instance, East Sussex CC was able to fill 65,144 potholes last year - 907 more than in 2013.
The DfT anticipates its latest wave of local road maintenance allocations - worth £976m annually - will help fill around 18m potholes across the country. An incentive fund worth £578m is also due to open in 2016 to reward councils that demonstrate they are delivering value for money by carrying out cost-effective improvements.
Chris Shields, service leader for Ringway Jacobs, Cheshire East Highways, speaks of the ‘huge development’ in techniques and materials over the past decade, yet emphasises the need to match such progress with correct application.
‘To go alongside the technological advances, the key things are longer-term investment and better planning. Engineers of today have more tools than ever. It’s more about the right treatment at the right time. All kinds of repairs for carriageways are always far better and more efficient when treating defects at the right time and in the right conditions,’ Mr Shields says.
• A longer version of this feature first appeared in Surveyor magazine. Visit www.transport-network.co.uk/subscribe to subscribe.
