> Obviously salt is the cheapest, otherwise it wouldn't be in such high use.
Not sure why you would assume that's obvious. The various solutions vary in effectiveness due to a number of factors, and are not equal in what they actually do. Sand doesn't melt ice, it provides traction. It's better when it's cold enough for the ice to stay ice. Salt melts ice, but is less effective in lower temperatures, and causes lots of fallout (corrosion, etc). Meanwhile plowing is the only real solution for heavy snowfall.
A small thing to add, not all road salt is the same. Some contain additional additives that allow them to be effective at lower temperatures. From what I recall, the low temperature salt is more expensive though.
Not sure why you would assume that's obvious. The various solutions vary in effectiveness due to a number of factors, and are not equal in what they actually do. Sand doesn't melt ice, it provides traction. It's better when it's cold enough for the ice to stay ice. Salt melts ice, but is less effective in lower temperatures, and causes lots of fallout (corrosion, etc). Meanwhile plowing is the only real solution for heavy snowfall.