Advice for driving in fog: when to use your fog lights

Advice for driving in fog: when to use your fog lights
Fog lights need to be used at the right times to combat reduced visibility otherwise you could be a danger to yourself and other motorists.

Foggy conditions can be extremely dangerous to help motorists drive to the best of their abilities in these types of weather conditions the RAC has put together a guide of useful information on how to drive in fog and when to use your fog lights.

In this guide we will cover:

What should you 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 phenomenon called freezing fog

When should you use your car fog lights?

  • Fog lights should only be used in the fog, when visibility drops below 100 metres (328 feet) which is roughly the length of a football pitch, this is stated by the Highway Code (rule 226).
  • Not using your fog lights when appropriate could impact upon the safety of yourself and those around you when driving. 
  • If while driving in fog your car is involved in an accident and you weren't using your fog lights, it could invalidate your insurance.

Fog lights and when to use them

Use your common sense. If the fog is so severe that you’re struggling to see other vehicles, switch on your fog lights. But don’t keep switching them off and on again, as this can confuse other drivers.

Is it ever against the law to drive with your fog lights on?

Yes, the Road Vehicles Lighting Regulations 1989 prohibits the use of front and rear fog lights to dazzle other drivers when visibility is not reduced or when the vehicle is parked. Using fog lights in drizzle and rain is therefore not allowed.

You are even eligible for a fine from the police if caught.

Once the fog has lifted, switch off your fog lights. There will be symbol on your car’s dashboard or on the fog light button itself: it’s normally an amber indicator for rear fog lights and a green one for front fog lights.

READ MORE: Is it illegal to drive with snow on your car?

How to check your lights and bulbs

It is highly advisable to check your lights before setting off.

During the autumn/winter season when there is more chance of fog it is key to ensure your car is in the best running state to tackle the conditions before it, meaning it is highly advisable to check your  lights are working before setting off.

Make sure you’re familiar with how to operate your front and rear fog lights before setting off, and don’t confuse these with your vehicle’s ‘full beam’ setting.

Daytime running lights and fog

If your car is fitted with automatic lights activated by low light levels, remember to check the lights are on, as they may not be automatically activated in foggy conditions.

READ MORE: What actually is fog and what causes it?

Similarly, drivers whose vehicles have daytime running lights should ensure rear lights are switched on as most vehicles with this feature only illuminate the front lights.

Do all cars have to have fog lights?

All cars must be fitted with rear fog lights as it’s a legal requirement. If your car has been imported, it will need a rear fog light before it is allowed to be used on the road.

Front fog lights are not a legal requirement, but if your car has them you should only use them when visibility is severely restricted.

READ MORE: How to drive safely in the rain and through floods

MORE ADVICE: How to demist your windscreen in double-quick time