What Should You Do When Driving in Fog? UK Safety Guide

When driving in fog, you should slow down, switch on your dipped headlights, increase your following distance and stay alert to hazards. According to the UK Highway Code, headlights must be used when visibility is seriously reduced, generally below 100 metres. You may also use front or rear fog lights, but you must switch them off when visibility improves.

Fog makes it difficult to see other vehicles, pedestrians, junctions and road signs. Whether you’re a learner or an experienced driver, understanding how to adjust your driving in fog is essential for staying safe on UK roads.

Key Takeaways

• Reduce your speed before entering fog and check your mirrors.
• Use dipped headlights when visibility is seriously reduced.
• Only use fog lights when visibility is seriously reduced, generally below 100 metres.
• Increase your following distance and avoid sudden braking.
• Avoid using full-beam headlights because they can create glare.
• Follow Highway Code Rules 226 and 234–236.

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What Should You Do When Driving in Fog?

The safest approach is to adjust your speed, lights and following distance according to how far you can see ahead. Here are seven important precautions.

1. Slow Down Before Entering Fog

Fog can reduce visibility suddenly, especially on motorways and country roads. Check your mirrors and gradually reduce your speed before entering a foggy area.

Drive slowly enough to stop well within the distance you can clearly see. Even if the road appears empty, another vehicle or obstruction could be hidden ahead.

2. Use Dipped Headlights, Not Full Beam

Dipped headlights help you see the road while making your vehicle visible to others. Full-beam headlights can reflect off fog droplets, creating glare that makes visibility worse.

Do not rely entirely on automatic headlights or daytime running lights, as they may not activate the necessary lighting in foggy conditions.

Learn more in our guide to dipped headlights or full beam.

3. Increase Your Following Distance

Leave more space than usual between your car and the vehicle ahead. Fog reduces the time available to react if traffic suddenly slows or stops.

The normal two-second gap is a minimum guideline for good conditions. In fog, you should leave considerably more room depending on visibility and road conditions.

Avoid following another vehicle’s rear lights too closely, as this can create a false sense of security.

4. Keep Your Windscreen and Mirrors Clear

Condensation and moisture can make visibility even worse. Use your windscreen demister, wipers and rear-window heater when necessary.

Before starting your journey, check that your windows, mirrors, headlights and wiper blades are clean.

A clear windscreen is particularly important when approaching junctions, roundabouts or busy roads.

5. Avoid Unnecessary Overtaking

Overtaking in fog is dangerous because approaching traffic and bends may be difficult to see.

Stay in your lane where appropriate, avoid unnecessary manoeuvres and never overtake unless you have a clear view of the road ahead.

6. Take Extra Care at Junctions

Approach junctions and roundabouts slowly, as fog can hide approaching vehicles, cyclists and pedestrians.

Check carefully in both directions. At junctions with restricted visibility, stop in the correct position and listen for traffic when necessary.

Only proceed when you are sure there is enough space to complete the manoeuvre safely.

7. Stop Safely if Visibility Becomes Too Poor

If fog becomes so thick that you cannot continue safely, consider stopping somewhere suitable until conditions improve.

Use a car park or service area where possible. Never stop on a motorway hard shoulder simply to wait for fog to clear.

What Does the Highway Code Say About Driving in Fog?

The UK Highway Code includes specific rules for driving in fog.

Rule 226: You must use headlights when visibility is seriously reduced, generally below 100 metres. Fog lights may also be used, but you must switch them off when visibility improves.

Rule 234: Before entering fog, check your mirrors and slow down. Be prepared for sudden patches of thick fog, even when the road initially appears clear.

Rule 235: Keep a safe distance from the vehicle ahead, use your wipers and demisters, and ensure you can stop within the distance you can clearly see.

Rule 236: You must not use front or rear fog lights unless visibility is seriously reduced, as they can dazzle other drivers and obscure brake lights.

These rules help drivers make safer decisions when road visibility changes unexpectedly.

When Should You Use Fog Lights While Driving?

You may use fog lights when visibility is seriously reduced, generally when you cannot see more than 100 metres ahead.

Front fog lights help illuminate the road immediately ahead, while rear fog lights help other motorists see your vehicle.

However, fog lights must be switched off once visibility improves because their brightness can dazzle other road users.

For more information about vehicle lighting, read our guide to using car sidelights.

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What Should You Do When Driving in Fog on a Motorway?

Motorway driving in fog requires particular caution because vehicles travel at higher speeds and stopping distances can be considerable.

Follow these precautions:

• Reduce your speed gradually after checking your mirrors.
• Maintain a greater distance from the vehicle ahead.
• Follow electronic speed limits and fog warnings.
• Avoid unnecessary lane changes and overtaking.
• Never accelerate because another driver is following too closely.

If visibility becomes too poor to continue safely, leave the motorway at a suitable exit or service area.

How Can Learner Drivers Prepare for Driving in Fog?

Learner drivers should understand how poor visibility affects speed, stopping distances and hazard awareness.

Before driving, learn how to operate your vehicle’s dipped headlights, fog lights, windscreen wipers and demisters. Practise adjusting your speed and maintaining safe distances under your instructor’s supervision when conditions are suitable.

Our regular driving courses at SUJA Driving School help learners develop road awareness, vehicle control and safer driving habits.

You can also explore our pay-as-you-go driving lessons to gain additional practical driving experience at your own pace.

Conclusion

When driving in fog, reduce your speed, use dipped headlights, maintain a safe following distance and stay alert to changing road conditions. Avoid full-beam headlights, unnecessary overtaking and sudden braking.

Always follow the UK Highway Code and ensure you can stop within the distance you can clearly see ahead.

Frequently Asked Questions

What should you do first when driving in fog?

Check your mirrors and reduce your speed before entering fog. Use dipped headlights when visibility is seriously reduced, increase your following distance and watch carefully for hazards.

What lights should you use when driving in fog?

Use dipped headlights when visibility is seriously reduced, generally below 100 metres. You may also use front or rear fog lights. Avoid full-beam headlights because they can reflect off fog and reduce visibility.

What should you do when driving in thick fog?

Reduce your speed significantly, increase your following distance and use the correct lights. Make sure you can stop within the distance you can clearly see. If conditions become too dangerous, stop somewhere safe.

What is the 100-metre rule when driving in fog?

The Highway Code requires headlights when visibility is seriously reduced, generally below 100 metres. Front or rear fog lights may also be used, but they must be switched off once visibility improves.

What should you avoid doing when driving in fog?

Avoid speeding, using full-beam headlights, following other vehicles too closely, sudden braking and unnecessary overtaking. You should also avoid relying entirely on automatic lights or driving too fast for the available visibility.