Travelling in fog

Fog is a major travel hazard which can affect visibility. It occurs most often in late autumn and towards the end of February, but can be a problem throughout spring and autumn.

Travelling in fog

Fog often disperses after sunrise but on occasions may last all day or several days.

Before you travel

Always check your vehicle.

Make sure you’re familiar with how to operate your front and rear fog lights.

As with any journey, it’s always best to plan ahead and look at the latest weather forecasts before you travel.

When you’re on the road

Use dipped headlights, wipers and demisters. Avoid using full beam, as the fog reflects the light back, reducing visibility even further.

According to the Highway Code, you should use your headlights when visibility is below 100 metres (328 feet).

Use fog lights only when visibility is seriously reduced and below 100 metres (328 feet).

Only drive as fast as conditions allow:

  • Create a bigger gap between you and the vehicle in front of you
  • Slow down so you can stop within the distance you can see clearly.
  • Check your mirrors before you slow down, brake slowly

Beware of other drivers not using headlights.

Note: occasionally while driving, your visibility may be affected by smoke or dust. In these situations, you should follow the same advice as for driving in fog.

Follow the Highway Code's advice on foggy weather.

How we help you

On parts of our network we use fog detection systems, which will automatically set our roadside signs to warn you when visibility is reduced.

Fog can be very localised - sometimes signs may indicate fog, but nothing is present at that location.

Top tips for driving in fog

Listen out for other vehicles

If visibility is very limited, wind down your windows at junctions and crossroads to allow you to listen out for approaching traffic.

Keep your windscreen clear

Ensure the heater is set to windscreen de-misting and open all the vents.