Winter is upon us, and that usually means snow, ice or at least a thick film of frost on every pavement and road first thing on a morning. While pedestrians will have to try their best not to slip, motorists have more to be wary of at this time of year. Winter is the most difficult time of year for drivers, as they have to contend with patches of black ice, heavy snow drifts, freezing rain or, at the very least, a few patches of frost that show no signs of thawing.