How does salt work on the road?

As salt is spread over the roadway, it forms a brine (moisture and salt) as the snow and ice melt. The snow and ice that remain float on the brine, breaking the bond with the roadway. As more traffic passes over the surface, slush is formed which can be plowed to the sides of the road. Plowing alone cannot accomplish this. Salting and plowing together make safer roadways. The brine’s freeze point is lower than zero and breaks up the bond formed between the road and the snow. Temperatures, time of application, weather conditions and the type of road surface, are among the many variables that can affect the success of deicing. For instance, at 30° F salt is five times more effective than at 20° F.