Driving in fog: when to use fog lights

Using them at the right time should aid safe driving but using them at the wrong time could mean you are breaking the law and endangering other drivers.

To help motorists stay as safe as possible we have put together a guide of useful information on how to drive in fog and when to use your fog lights.

5 tips for driving in fog

Fog light symbol

These are the fog light symbols you're looking for if you want to switch them on.

They can usually be found on a button on the dashboard, on a steering wheel stalk, or next to the dial you use to control your regular lights.

Here's what your fog light switch might look like on a steering wheel:

Front fog light

The one showing a lamp pointing to the left and with lines pointing diagonally down through the vertical wavy line is for your front fog lights.

Rear fog light

The one pointing in the opposite direction, with lines pointing horizontally straight through the wavy line is for your rear fog lights.

Take a look in your vehicle's logbook if you can't track them down or work out how to switch them on.

What to do when driving in fog

• Before entering fog, you should check your mirrors, then slow down
• Maintain a greater distance between you and the car in front, you could increase the gap to four seconds from the recommended two
• Make sure to use your wipers and to keep your windscreen demisted to aid visibility
• If the word ‘fog’ is shown on a signal, but the road is clear, be prepared for a sudden bank of fog or drifting, patchy fog
• Use your lights if visibility is reduced to 100 metres (328 feet) or roughly the length of a football pitch
• Make sure you know where your fog-light switch is before you set off
• Do not use full beam, because the fog reflects the light back, reducing visibility even further
• Do not attempt to navigate using the tail lights of the car in front, as these can give a false sense of security
• If visibility is very limited, wind down your windows at junctions and crossroads to allow you to listen out for approaching traffic
• If you really cannot see, you should consider stopping until it is safe to continue.

Did you know that mist and fog are actually very different things? There is also a worryingly-named phenomenon called freezing fog.