A view of a woman through a rainy windscreen

A guide to driving in foggy conditions

5 minutes

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Knowing the regulations around driving in fog can help you stay safe. Find out when to use your fog lights and how to drive safely in foggy conditions...

  • A break down of the key classifications of fog and mist
  • Answers to the most searched questions about driving in fog
  • When to turn your fog lights on, and when to turn them off

Fog is common in the UK in autumn and winter. 

Driving in foggy conditions 

Foggy weather significantly affects your vision of the road ahead, reducing the time you have to react to potential hazards on the road. Driving without due care and attention in fog could put you at risk of having an accident, which, at the very least, could lead to a claim on your car insurance.

Fog can occur at any time of year but is more common during the autumn and winter months. Reduced visibility is not the only difficulty driving in fog can present. Colder conditions can bring frost and ice too, which can reduce stopping times and make roads slippery to drive on, so it's best to adjust your driving style to suit the conditions. 

Below are answers to seven common questions about driving in fog. 

1. When should you use your fog lights?

The Highway Code (rule 226) says that you can turn your fog lights on when visibility on the road has dropped below 100m . 

If you're travelling 30mph, you should cover 100m in roughly eight seconds. To judge the distance, choose a fixed point on the road ahead of you just as it emerges from the fog, such as a sign, and count the seconds as you approach it. If you get any higher than eight, it's time to turn your fog lights off.

2. Is driving without fog lights illegal in foggy conditions?  

It’s not illegal to drive without your fog lights in poor conditions, however, it’s best to do so as they help other drivers spot you from a distance. You are legally obligated to use your headlights in foggy conditions, however. 

Make sure you switch your fog lights off as soon as visibility improves, or as you approach vehicles going in the opposite direction.

3. Is driving with fog lights illegal when it’s not foggy?

Driving with your fog lights on when it is not foggy is illegal. Make sure you switch them off as soon as the fog clears. 

Fog lights can dazzle other road users, while rear fog lights can obscure your own brake lights, preventing the vehicle behind you from seeing when you're braking.

If it’s a little foggy but you can still see beyond 100m, using your headlights may be a better option. 

4. How can I prepare for a driving in fog?

Before driving in fog, make sure your mirrors are clean and you have demisted your front and rear windscreen. Fill up your windscreen wash so you can use your wipers to keep your screen clear.

Make sure you take a high-vis jacket and a warning triangle with you in the car in case of an accident.

When you’re approaching fog on the road, check your mirrors and slow down as it is safe to do so.

5. What are the different types of car lights?

There are several different types of lights you might use for driving assistance in poor conditions. Including:

Driving lights - drivers who experience difficult driving conditions regularly may install driving lights on their vehicle, but you're unlikely to need them on UK roads. Driving lights are strong lamps that emit a focused white beam.

Fog lights - fog lights have a wide, flat beam meant to illuminate the road and the surroundings ahead.

Daytime running lights – these automatic headlights come on whenever the engine turns on. Newer cars often have daytime running lights installed over the standard headlights as they can make it easier for other drivers to see the car at any time. Daytime running lights are unsuitable for night-time usage, so they turn off automatically when headlights are switched on.

6. What if my car doesn't have fog lights?

If you're struggling to find your car's fog lights, they may be labelled as something else.

Some newer cars have the equivalent of fog lights integrated into their headlamps and rear lamps. 

Read your car manual to find what your vehicle has instead of fog lights, and then turn them on while parked to see how bright they are. They may be called 'all-weather lights' or something similar. If your manual doesn't have the information, ask at the car manufacturer's local dealership or have a look for an online manual.

If your car definitely doesn't have fog lights, judge whether your head and rear lights will be strong enough for driving in fog. 

7. Will I be okay if my car has automatic headlights? 

No, you’ll need to turn your lights on manually. If your car is relatively new and has headlights that switch automatically as it gets darker, don’t wait until they come on when driving through fog as it may not be dark enough to trigger the automatic sensor. 

Tips for staying safe when driving in fog

Rule 235 of The Highway Code shares the following advice for drivers in fog

  • Keep a safe distance behind the vehicle in front. Rear lights can give a false sense of security.
  • Make sure there is ample braking space between you and the vehicles around you. 
  • Be aware of other drivers not using headlights.
  • Don't accelerate to keep a distance between cars that are behind you. 
  • Check your mirrors before you slow down. Then use your brakes so that your brake lights warn drivers behind you that you're slowing down.
  • Stop in the correct position at a junction with limited visibility and listen for traffic. When you're sure it is safe to emerge, do so positively and don't hesitate in a position that puts you directly in the path of approaching vehicles.

Fog can drift over the UK at any point of the year, so be careful on the roads and check out weather reports before taking a drive. If you do your checks beforehand, you're familiar with your lights, and you go at a steady speed, you'll be well prepared. Read the full checklist for staying safe on the road. 

Make sure you’re protected in the event of an accident, in fog or otherwise, with car insurance from LV=. 

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