For a country where rain and cold weather is as common as oxygen, you would think sunshine can only be a good thing. And it is ─ unless you are planning on driving on a motorway.
Junction 23 of the M25 motorway near Potters Bar, Hertfordshire had to be closed on Sunday because it had melted, causing thousands of commuters and holiday-makers to endure temperatures of up to 31.4 degrees Celsius while sat in traffic.
Such was the ‘severe damage’ caused by soaring temperatures, the police had to close the clockwise carriageway while the Highways Agency attempted to warn drivers about the possibility of jams and slow-moving traffic. Motorists spoke of cars ‘ploughing into’ the road surface as if it was a liquid and there was even talk of a visible ridge appearing just after 3pm.
“It is too early to say exactly what caused the road to deteriorate in such a manner but right now the top priority is to complete the resurfacing work, which is at an advanced stage, so that the M25 can be re-opened to traffic before the Monday morning rush,” a spokesperson for the Highways Agency said.
Chief executive of the Road Surface Treatments Association Dr Howard Robinson told the BBC that most busy roads in the UK will start to soften at 50 degrees Celsius and “regularly” do. Not a problem for the UK, you would think, except direct sunlight on a dark surface can cause the ground temperature to exceed the threshold.
“Asphalt is like chocolate – it melts and softens when it’s hot, and goes hard and brittle when it’s cold – it doesn’t maintain the same strength all year round,” Robinson explained.
While the Government is unable to control the weather – as far as we can tell – it can at least ensure roads are better equipped. After a heat wave in 1995, an asphalt surface was introduced that, thanks to a tweaked specification, increased the softening point of tarmac to 80 degrees Celsius, reducing the chance of melting motorways. Unfortunately, due to the cost and use on busy roads, only an estimated 5 per cent of the UK’s road network benefits.
This is not the first time the M25 has got hot and near enough give up its occupation as a road. Record-breaking temperatures (35.3C) in August, 2003 caused the closure of two lanes between Junction 26 and 27.