Wisconsin is the largest producer of cheese in the US, which means it has a great deal of waste product as part of the cheese-making process. One of the primary byproducts of cheese production is salt water in the brine, which can apparently be repurposed to deice roads.
The Times reports that the salt water is being mixed with a regular ol' rock salt as part of a trial program in Milwaukee. If the trial proves successful, authorities expect other states would implement their own salt-cheese blends. As for what cheeses work best? It seems that roads are partial to provolone and mozzarella (coincidentally, so is your author). Scroll down for a local news report.