Fog

If you suddenly encounter a fog bank, your visibility can go from good to zero in a matter of seconds. When driving in fog, lower your speed and increase your cushion to your front. As is the case with heavy snow, use headlights on low beams only. If you are having difficulty driving in the fog, safely pull completely off the road and keep your lights on. Resume travel when visibility improves. Fog banks can disappear just as fast as they show up.