When Do You Use Fog Lights? And What Are They?

Modern cars have a bewildering array of lights and it is easy to become confused about what to use and when, especially when so many models now have automated headlamps which take care of most of the decision making for us.

However, even the most sophisticated car can’t yet decide when to switch on your lamps to drive in fog.

What Are Fog Lights?

Fog lights are special vehicle lights designed to improve visibility when weather conditions make it difficult to see the road or other vehicles. Unlike standard headlights, fog lights have a wider, flatter beam pattern that helps illuminate the road immediately in front of the vehicle without reflecting back into the driver's eyes.

There are two types of fog lights:

• Front fog lights help drivers see the edges of the road in poor visibility.
• Rear fog lights help other road users see your vehicle from behind.

Fog lights are particularly useful during fog, heavy rain and snowfall, when normal headlights may not provide enough visibility.

When Should You Use Fog Lights?

According to Rule 226 of the Highway Code, you should only use fog lights when visibility is seriously reduced, generally when you cannot see more than 100 metres (328 feet) ahead. That's roughly the length of a football pitch.

Fog lights may be appropriate when driving in:

• Dense fog
• Heavy snowfall
• Severe rain that significantly reduces visibility

The purpose of fog lights is to help you see and be seen when normal lights are not enough. However, they should only be used when conditions genuinely require them.

When Should You Not Use Fog Lights?

Many drivers leave their fog lights on longer than necessary, but this can be dangerous and irritating for other road users. You should switch off your fog lights as soon as visibility improves beyond 100 metres.

Fog lights should not be used in:

• Clear weather
• Light rain
• Light mist
• Normal night-time driving

Rear fog lights are particularly bright and can make it harder for drivers behind you to judge braking distances. Incorrect use can also result in a fixed penalty notice.

How do I know my car has fog lamps?

If it was built after 1st April 1980, your car will have at least one fog lamp button on the dashboard as it is a legal requirement. This law was brought in to prevent accidents where following drivers have not been able to see other vehicles in poor conditions. Many vehicles will also have front fog lights fitted, although these are not compulsory and are primarily designed to help the driver see more of the road.

They are different to the daytime running lights which are fitted to modern cars and can only be used when the sidelights or headlamps are turned on.

You will be able to find the switch (or switches, if you have front fog lights too) either in a prominent place on the dashboard or on the same stalk behind the steering wheel as the other lighting controls – usually on the left side. When they are illuminated, there will be a warning light on the instrument panel.

It’s best to know where they are before you set off on a journey so you’re not distracted while driving, especially as the poor conditions will require all of your attention. The experts at Eden will be happy to show you how to use the controls when you pick up your new car.

When may front fog lights be used

According to the Highway Code (rule 226), fog lights should only be used when visibility drops below 100 metres (328 feet) which is roughly the length of 20 cars or a football pitch. You should turn them off as soon as the conditions improve, as they can be distracting and dazzling to other road users and will make your brake lights less discernible.

Besides being inconsiderate to other drivers, you can also be fined £30 for misusing your fog lights.

Are foglights checked in a MOT?

Yes. Rear fog lights are part of the MOT inspection and must be working correctly if they are required for your vehicle.

For vehicles first used after 1 April 1980:

• Rear fog lights must operate correctly
• The dashboard warning light must function
• The light must display the correct colour (red)

Why do some modern cars not have front fog lights?

Many modern vehicles now use advanced LED and matrix LED headlights that can automatically adapt their beam pattern to changing driving conditions.

These systems can often provide better visibility than traditional fog lights, which is why some manufacturers have stopped fitting separate front fog lights altogether.

Instead, the vehicle's main headlights can adjust their brightness, direction and beam spread to improve visibility in poor weather conditions.