What the D.O.T. puts on the road in snowy weather to clear it enough so that you can drive "safely and sanely" --- in other words, so that your car maintains a straight level path and keeps all four wheels on the road instead of doing twirlies or back-flips, i.e., "summer salts".
I usually walk to the store during snowy periods so that my car doesn't get rotted out underneath from all the winter salt on the road.
by QuacksO January 12, 2017