> before it can form a sheet of ice. I think the person is just saying that pre-emptively salting the road (before snow/freezing rain actually lands) provides

> before it can form a sheet of ice. I think the person is just saying that pre-emptively salting the road (before snow/freezing rain actually lands) provides some additional level of safety because the road might spend less time with a frozen coating (as opposed to salting only after the surface is frozen over).