How to use your fog lights and drive safely in fog

What are fog lights?

Fog lights are extra front and/or rear lights on some vehicles that are designed to make it easier to see and be seen in foggy conditions.

• Front fog lights are usually white or yellow lights which sit below your headlights and can cut through fog without causing glare.
• The rear fog light is a red light, similar in brightness to a brake light, on the back of your car which helps other drivers see you.

What’s the difference between fog lights and headlights?

When fog reduces visibility, the moisture in the fog reflects the light from normal car headlights back, making glare worse.

The difference between fog lights and normal headlights is how they cut through fog to reduce glare:

• Front fog lights are designed to shine downwards to illuminate the road below any hovering fog.
• The top of the beam is cut off sharply so that the lights won’t reflect back off the fog.
• They’re mounted lower down on the car so they can shine underneath the fog.

Normal headlights aren't angled downwards in the same way and are mounted higher up on the front of the car.

Does my car have fog lights?

It’s the law for cars to have a rear fog light. Many have front fog lights too, but some modern cars use daytime running lights instead of front fog lights.

You can check your dashboard, steering wheel stalk or vehicle hand book to see if your car has front fog lights.

When should you use fog lights?

Fog lights can help you to see and help other drivers see you if the weather is very misty or foggy.

• The Highway Code says you must use headlights when you can’t see for more than 100m in front of you.
• You can also use front or rear fog lights but this is optional.
• You must turn fog lights off when visibility improves so you don’t dazzle other drivers.

If you’re not sure, it’s best to use your common sense. You don't have to use fog lights, but your insurer might take issue if you're in an accident in poor visibility and they weren't on.

What if you have automatic lights?

Almost 1 in 10 drivers* say they rely on their car’s automatic lights all the time. But automatic lights won’t come on if it’s foggy but bright, as they rely on light-level sensors.

Check whether you need to switch yours on manually. And watch out for almost-invisible cars whose drivers haven’t got theirs on.