How does gritting salt work?

How does gritting salt work? Salt reduces the freezing point of water. So, when the road is wet and starts to freeze, gritting salt prevents the formation of ice. The effectiveness of gritting salt also depends on the grain size.

Smaller grains work more quickly but their effectiveness diminishes rapidly. Coarse gritting salt works more slowly but its effect lasts much longer. That is why good quality gritting salt offers a blend of smaller and large grains.