Fog is a thin layer of cloud resting on the ground. Fog can reduce visibility for drivers, resulting in difficult driving conditions.
The best thing to do is to avoid driving in fog. Check weather forecasts and if there is a fog warning, delay your trip until it clears. If that is not possible or you get caught driving in fog, there are a number of safe driving tips you should follow. If visibility is decreasing rapidly, move off the road and into a safe parking area to wait for the fog to lift.