Fog driving and reduced visibility

Fog is one of the most dangerous weather situations in traffic. Visibility can drop below 50 meters, and you lose track of the road, other road users and potential hazards.

Rules for light in fog

• High beam should never be used in fog. The light reflects back and makes visibility worse.
• Rear fog lights are only allowed in visibility below approx. 100 meters, because the bright red light can dazzle the car behind.

Read more about the use of light in driving in the dark .

Adapt your speed to your visibility

The main rule is that you should be able to stop on a visible stretch. This means that the stopping distance should never exceed the distance you can actually see.

• At 50 metres of visibility, the speed should not exceed 40-50 km/h.
• Keep an extra long distance from the car in front.
• Use road markings and borders as reference points.
• Lower the window slightly to hear traffic you don’t see.

See Stopping Distance Calculation for the relationship between speed and stopping distance.

Other situations with reduced visibility

• Heavy rain and snow showers can give visibility similar to fog.
• Splashes from large vehicles can severely reduce visibility on the highway.
• Sunrise and sunset in combination with humidity occasionally cause fog banks.
• Valley and areas near water are particularly vulnerable to local fog.

Pay attention to weather and weather warnings before you set out on a trip.

Important rules of the road in fog

• Never stop on the roadway.** Find a parking space or bus space.
• Use turn signals well in advance so that the car behind can see you.
• Use extra caution in curves where the fog may become denser.
• Avoid overtaking other cars unless absolutely necessary.

Further reading

• Speed and weather conditions
• Driving in strong winds
• Solar glare and backlight
• Custom Speed & Hidden Hazard