Fog is one of the least frequent weather phenomena, but also one of the most annoying when driving on the road. It usually appears in areas with high relative humidity, either on the coasts in the form of a gale, or in the interior, concentrated in the valleys along the rivers. Winter days with low temperatures, but not enough to freeze, favor the presence of fog banks that can considerably hinder circulation.

The General Directorate of Traffic (DGT) establishes a series of recommendations to combat the loss of visibility associated with fog and mitigate the risk of accidents. This body advises drivers to take the line of the shoulder or, where appropriate, other vehicles as a reference to guide them along the road and requires them to use the car lights appropriately to be noticed by the rest of the road users.

Rear-end collisions are a potential hazard on foggy roads, partly because the road becomes wet and therefore the tires reduce their grip on the asphalt. If you add to this the possibility of ice sheets forming in freezing temperatures, the braking distance increases considerably. In these circumstances you must adjust the speed to your field of vision and increase the safety distance. Also try to step on the brake gently to avoid skidding the car.

The thickness of the fog can prevent you from seeing vehicles or obstacles that are a few meters ahead. That is why, even if you are on a road with several lanes in each direction, always try to drive in the right lane. In the case of conventional roads, overtaking is prohibited if visibility is very low. And if the fog is so thick that mere traffic is dangerous, leave the road until it clears up.

The lights are a necessary precaution to make yourself visible not only to other drivers, but also to more vulnerable groups, such as motorists, cyclists and pedestrians. The use of the front fog lights as a reinforcement to the dipped lights is mandatory in case of fog. They must be properly adjusted at a height that allows you, on the one hand, to clearly see the lines of the road, and on the other, so that it does not dazzle the cars ahead.

You should turn on the rear fog lamps simultaneously when driving through banks of dense fog or during heavy rain or snowfall so that drivers behind you can see you clearly. In traffic jams or when the fog subsides, you should turn it off so as not to dazzle. Do the same with the headlights and never use high beams for these cases, as it will be counterproductive and will only reduce visibility for you and others.