Fog lights are specially designed to improve visibility in foggy conditions.

In thick fog, optical effects can impair driving. Fog lamps are precisely designed to correct these optical effects and guarantee greater safety. When visibility on the road is not sufficient for the driver to understand the driving environment and its dangers, it is essential to use the vehicle's headlights. As each headlamp or light has its specific function, it's essential to explain the use of each type of light, and in particular front and rear fog lights, which help you to see and be seen better when driving in difficult weather conditions.

Front fog lights

If visibility on the road is less than 150 m, motorists can be seriously inconvenienced. Front fog lights are there specifically to help you drive when you need more light. You avoid any risk of self-glare, while still being able to detect any obstacles close to the sides of your vehicle.

Rear fog lights

In general, rear fog lamps are used to warn other drivers of your presence on the road. When there's a lot of fog or snow, visibility is greatly reduced.

Optical effects in foggy conditions

• The halo effect surrounding light sources.
• The haze effect, which reduces the sharpness of obstacles and makes them blurred.
• Extinction, i.e. the visual disappearance of certain obstacles.

Fog lights are rarely used in cars. However, in hazardous conditions, such as thick fog, they are indispensable!  Low-beam headlamps are not powerful enough to counter these optical effects. In such cases, it's best to use front fog lights and rear fog lights, which are the most powerful car headlights and offer a wider area of illumination.

Which lights to use in fog?

As soon as visibility is impaired, it's a good idea to switch on the low beam. This applies not only to fog but also to rain or snow, for example. Fog lights should be switched on when visibility is very poor, i.e. in dense fog. Front fog lights illuminate the edge and center of the road to help you stay on course. Rear fog lights enable you to be seen by drivers behind you. When the fog clears, don't forget to switch off your fog lights, so as not to dazzle other motorists.

Tips for driving in fog

In fog, if visibility is reduced to less than 50 meters, the use of fog lights alone is not enough to ensure your safety. In such conditions, you should drive at a maximum speed of 50km/h and increase your safety distances to avoid pile-ups. Don't risk overtaking other drivers either, as fog masks obstacles and distorts your appreciation of distances. Finally, stay in the right-hand lane for maximum safety.

Fog lights: under what other conditions can they be used?

Among the lights to use in the rain, front fog lights improve visibility in heavy showers. Be careful, however, never to switch on the rear fog lights when it's raining, as this will dazzle other road users.

Heavy snowfall can also create a kind of "veil" that radically reduces your vision and visibility. In such cases, you can switch on your front and rear fog lights in addition to your low-beam headlights, to improve your visibility and that of other road users.

Fog lights can therefore improve visibility on the road, but they don't reduce all the risks associated with bad weather! Beware of freezing fog, for example, whose water droplets freeze on contact with the road surface.