The Wisconsin Department of Transportation is the authority in charge of maintenance of the state highways and their statewide policy is to use straight rock salt to assist in melting ice and snow from those pavements.
Price County is the authority in charge of the maintenance of the county highways and that policy requires the use of a sand / salt mixture with 5% salt.
Using only the salt increases the deicing rate of the roadways, but at a much higher cost than the sand / salt mixture. The price per ton of salt is $92.59 and the price per ton for the sand / salt mixture is only $17 per ton.