When driving in fog you should remember these tips

Use your low beams. The visibility in front of you will sharply decrease in a fog, so use the vehicle's low beam lights (if the vehicle does not have fog lights or driving lights). Heavy fog conditions prohibit use of high beam headlights. The light from high beam headlights will be reflected back by thick fog. As fog thins, high beams can become more effective. Check periodically to see if the fog has thinned enough to make use of high beams.