Sensors installed at three locations along Interstate 40 west of Flagstaff, Ariz., are helping the Arizona Department of Transportation detect and address icy road conditions before they are present.

The roadway sensors are connected to ADOT Road Weather Information System locations that use cameras and instruments to provide up-to-date conditions.

Each location has a sensor to measure the salt content of road surface moisture, which affects the freezing point. Another sensor is used to measure the temperature of the ground underneath the road.

The information is combined with data from the Road Weather Information System and National Weather Service to forecast the likelihood of ice forming. The program can also alert operators if the pavement temperature drops below a certain threshold. This helps ADOT determine whether to send crews out to spread deicing material.

“Technology can provide us with another way to keep motorists safe as they travel to Arizona’s colder regions,” said Audra Merrick, district engineer for ADOT’s north central district. “These sensors are another tool in ADOT’s toolbox to help keep the highways clear of snow and ice during winter season.”

Interstate 40 between Ash Fork and Flagstaff is more susceptible to icy roads due to its high elevation and freezing overnight temperatures. The road is also a priority because it see’s heavy traffic from commercial and passenger vehicles, according to ADOT.

So far, ADOT says that the data has been so helpful that it plans to install more sensors at additional high-country locations in the next few years. The three sensors cost $90,000 and were funded through ADOT maintenance funds.