The UK will soon be witnessing a futuristic plan to collect and recycle summer sunshine to keep roads ice-free in winter.
The Highways Agency plans to install pipes underneath a section of road to gather solar energy in summer and recirculate it in winter.
Experts hope the scheme could be a way to treat the roads which are the first to freeze. Officials are also testing the technology to heat and cool buildings, cut energy bills and lower greenhouse gas emissions.
If successful, the pilot scheme could be extended to more roads.
The scheme, known as interseasonal heat transfer, or IHT, will lay a network of plastic pipes filled with water just below the road surface.
In summer, when road temperatures can reach 40C, the water is warmed and pumped to pipes insulated with polystyrene. In winter, when sensors detect the temperature at 2C, warm water is pumped back under the road to heat the ground and prevent ice forming.
Because of the significant investment needed, only cold spots could be realistically considered at this stage, she said. "Salting of the road will not be replaced."
In cold countries, large quantities of rock salt are used to help clear highways of ice during winter, but "Road Salt" loses its melting ability at temperatures below -15°C to -20°C (5°F to -4°F). Recycling sunshine could be an interesting option under the circumstances.
The new plan follows a two-year trial on a little-used access road near Toddington services on the M1 by scientists at the Transport Research Laboratory (TRL) in Wokingham, Berkshire, writes David Adam in Guardian.
Scientists found enough heat was captured in the summer of 2006 to keep the road above freezing for almost all of the following winter. On average, the heated surface was 3C warmer than the surrounding ground.
The test also showed that heat from the road could be used to warm and cool surrounding buildings.
A school in Hatfield, Hertfordshire, is experimenting with similar pipes beneath its playground.
A larger version is used in Rotterdam to keep a motorway flyover free from ice and heat four office buildings.
A TRL report published last month said the under-road radiator pilot system would need to save councils about Ģ8,600 each year for 30 years to break even.
Henk Verweijmeren, head of Invisible Heating Systems, a company in Ullapool, Ross and Cromarty, which installs the technology, said a version underneath the firm's car park had collected enough energy over the summer to heat its offices last winter.
He said people are surprised by how much heat the system can produce.
"The potential of road energy is brilliant," he said. "It can generate half the energy of a solar panel placed on a roof at about a 12th of the cost."
A trial at an Edinburgh supermarket car park suggested that the system could cut the store's carbon footprint by 70% and slash annual fuel bills by Ģ26,000 for an initial investment of about Ģ180,000, he said.
Airports, which must use chemical sprays to ward off ice and snow - salt can corrode aircraft, which means airports need costly water purification plants - are also interested, including one in the UK.
Verweijmeren thought of the idea after spending Scottish summers moving sheep which were lying on the roads at night.
He found that the asphalt surface was much warmer than the surrounding ground area.
Most interest was coming from the US, he said, but some wealthy Britons had already invested.
"If you have a tennis court in your garden, then you can use the energy it collects to heat your swimming pool."