The Arizona Department of Transportation says sensors installed at three Interstate 40 locations near Flagstaff are helping forecast the likelihood of ice forming on the busy highway.
The freeway stretch between Ash Fork and Flagstaff is above 6,000 feet in most places and has heavy use by commercial and passenger vehicles.
The roadway sensors are positioned west of Flagstaff, west of Williams and on Ash Fork Hill.
They're connected to ADOT's Road Weather Information System locations, which use cameras and instruments to provide the latest conditions.
A computer program combines the information with data from the National Weather Service to forecast the likelihood of ice forming, helping ADOT determine whether to send crews out to lay de-icing material.
The three sensors cost $90,000 and were funded through ADOT maintenance funds.