While several chemicals are available for deicing winter roads, common salt (NaCl) is most frequently used. Approximately 20 billion lb (9 billion kg) of salt are used each year in the United States for treating ice and snow on roads. Calcium chloride (CaCl₂), potassium chloride (KCl), and urea are also available but used in smaller quantities. Common salt is preferred because it is cheaper per pound and more effective. While the price per pound of salt is cheap, about 1.5 billion dollars are spent per year on the enormous quantity used, and its distribution and application.

Salt in its solid form does not melt ice. It first must go into solution to form a brine, and the brine effects a melting of ice and snow. Ordinarily, snow is packed on the road surface by vehicular traffic; known as the "hard-pack," it forms a bond with the underlying pavement that...