Researchers at the University of Birmingham, in the UK, have developed road-temperature sensors that could save much of the country's expenditure on salting of winter roads. The internet-connected sensors have already been successfully trialed in Birmingham and London, among other places.

The sensors, whose development was funded by the Engineering and Physical Sciences Research Council, utilize WiFi networks to transmit data on road-surface temperatures to local authorities, highways agencies and other organizations that can use it to target precisely where salt is needed—and where it isn't. No cabling is necessary, deployment is rapid and sensor boxes are fitted unobtrusively near ground level on the street side of a lamppost or other fixed object.

By eliminating unnecessary salting, the sensors could save over £100 million per year. Image credit: EPSRC/Simon Bell. The hand-sized sensors, developed by meteorologists at Birmingham in conjunction with Oxford-based engineering firm Amey, cost approximately £200, compared with roughly £10,000 required to maintain a weather forecasting station like those currently used by local UK authorities to help them make decisions on when and where to salt roads.

In many instances, local authorities in the UK have only two or three such weather stations, which means the decisions they make are based more on forecasts than actual information, says Dr. Lee Chapman, who led the project. By contrast, the low-cost sensors could be deployed by the hundreds to enable decisions about the need to salt on a road-by-road basis.

"That's extremely useful in view of the fact that there can be a 10° to 15° Celsius difference in road temperatures across a county on a given winter's night," he says.

According to Chapman, the UK typically uses 2 million metric tons of salt in an average winter. He estimates that, by eliminating unnecessary salting, the new technology could enable savings of 20 - 50%—equivalent to over £100 million per year in salt for the country as a whole.

The real-time decision-making approach has the potential to be extended even further, the researchers say, with individual salt trucks switching their spreaders on and off continually in response to data generated by the sensor networks.

The researchers plan to work with industrial partners toward mass production of the sensors within the next two to three years.