With temperatures topping 30C, the heat is causing the bitumen in some roads to soften and rise to the top. This makes the surface sticky and more susceptible to pressure from heavy vehicles which can make parts of it sink, resulting in a ridge and furrow effect.
Areas where roads have been treated over the past few days include Cambridgeshire, Carmarthenshire, Cornwall, Essex, Hampshire, Lancashire, Northumberland, Glamorgan, Worcestershire and Yorkshire.
Most roads generally begin to soften when they hit a temperature of about 50C. A sunny day in the high 20Cs can be enough to generate 50C on the ground as the dark asphalt absorbs a lot of heat, steadily raising its temperature throughout the day.
Spreading rock dust or sand absorbs the soft bitumen, stabilising the surface of the road and making it less sticky and susceptible to warping.
Pembrokeshire Council has been forced to carry out emergency repairs to one of the main roads in Tenby.
The surface of a section of the A4218 known as Broadwell Hayes, between Serpentine Road and towards The Green, started breaking up in the hot weather.
Speaking to the BBC, councillor Rob Lewis, council cabinet member for highways and planning, said: “There is no doubt that the recent spell of extremely hot weather is responsible for the deterioration of the surface.
“It is very regrettable that we have to carry out this work on one of the busiest roads into Tenby at the start of the school holidays but we really have no choice. It would not be in the interests of safety to leave repairs until September.”
Cllr Peter Box, chair of the Local Government Association’s economy and transport board, added: “Snow and ice are the last thing on most people’s minds at the moment and I’m sure there’s been a lot of head-scratching if they’ve seen our gritters out on the roads in the height of summer. However, our gritting teams are once again playing a vital role in keeping the country’s roads safe for motorists.
This proactive work helps reduce the potential damage high temperatures can inflict on our roads, so keeping them safe and limiting disruption. Councils will continue to monitor road temperatures and once the weather cools will begin carrying out repairs if needed.
The last time there was widespread treating of roads by council gritters during the summer was in 2006 when temperatures reached the mid 30Cs.