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Which car lights to use and when

Let’s talk about the lights on your car. Many people think of this as an easy topic, but it’s important to be aware of all of the lights on your car – and how to use them, especially when driving at night, in the rain or fog.

Daylight running lights

Not to be confused with the low beams, daytime running lights are designed to make you more visible to other drivers. They usually consist of lights at the front and rear of your car which can turn on automatically when you start the engine. Local legislation may be different, but in general a modern car is configured to meet the local requirements.

Low beam headlights / dipped headlights

Unlike full beams (see next section), low beams (or dipped headlights) give enough light to show you where you are going without excessive glare that could dazzle oncoming drivers. Low beams are essential when driving at night, but they have also been proved to improve visibility and safety when used during the day, for example during adverse weather (rain, snow, sleet or fog) or just after sunrise and just before sunset. This is because during these times it can be more difficult to see other vehicles.

Full beam headlights

Just like the low beam headlights, full beam headlights help the driver to see the road in the dark. It also signals to other drivers where you are. Full beam headlights give an intense, centre-weighted distribution of light with a lot of glare. For this reason, they should only be used when it is difficult to see and there are no other cars visible in any direction, or you are at least 150m from oncoming traffic and need the full beams to see the road.

It is important to turn your full beams off in certain situations to avoid the risk of blinding or distracting oncoming traffic. This includes when cars are approaching you, even if they are on the other side of the motorway divider; in fog as light reflection can make it difficult for you to see; and on curves, on hills and at junctions as you have no way of telling if another car is coming towards you.

Fog lights

Fog lights with their unique flat and wide beam shape, are usually placed low on the front of the car, near the front bumper. The beam’s shape cuts through the fog to light up the surface of the road, while the position avoids light being reflected back and dazzling the driver. Cars also have at least one rear fog light to help other drivers spot your car. As fog lights are so strong they can distract other drivers, so they should only be used during fog or snow (but not in the rain) when normal headlights are ineffective.


Taillights are the red lights on the rear of your car that turn on automatically whenever your headlights are on. They let drivers coming up behind you know that you’re there and how far ahead you are.

Signal lights / indicators

Signal lights, also known as turn signals, indicators or blinkers, are located at the front and back of the car. Signal lights can also be found on your side mirrors. They are used to let other drivers know you are planning to turn and will probably need to slow down to turn.

Brake lights

Your brake lights tell other drivers that you’re slowing down or stopping. As they only turn on when you apply the brakes, you don’t need to think about when to use them.

Hazard lights

Your signal lights are also used as hazard lights, also known as flashers or hazard warning lights. When the hazard lights are turned on, they flash to warn other drivers of distress or traffic problems. For example, to warn other drivers of a hazard on the road ahead, when you’ve stopped and are causing a temporary obstruction or have broken down. They should not be used when you temporarily park.

Interior lights

Also known as driving lamps, these lights are useful for checking a map or directions or to find something in the dark. They shouldn’t be used when driving as they can distract the driver.

Which lights to use at different times of day

During the day

Daytime visibility in normal weather conditions is usually good which means you are not required to use any additional lights. However, a lot of modern cars use daytime running lights to improve your visibility to other road users (see above for more details).

Just after sunrise or just before sunset

Visibility starts to fall just after sunrise and just before sunset, that’s why it’s a good idea to use your low beams at these times of day.

At night

It is clear that driving at night is more difficult and requires more focus than driving during the day. That’s why it’s important to balance your need for light to improve your visibility with the needs of other road users. In other words, use your low beam headlights when other cars are around, and high beam headlights when you are at least 150m from other cars (see above for more details).

Which lights should you use in different weather conditions?

Which lights should you use in the fog?

Driving in fog can take some getting used to. To increase your visibility for added safety for you and your passengers, it’s important to use your fog lights (see above for more details). Additionally, remember to leave more distance between you and other cars and use the right hand edge of the road as a guide (or the left hand edge in the UK) so you don’t follow your natural tendency to drift into the middle of the road when visibility drops.

Which lights should you use in the rain?

This depends on your visibility: can you see more than 100m ahead of you through the rain? If so, it’s recommended to leave your low beam headlights on, but not compulsory. But, if you can’t see more than 100m ahead of you, you need to use your low beam headlights so that other drivers can see you easily. If visibility is very poor, you can also use your fog lights, but remember to turn them off as visibility improves.


The content contained in this article is for entertainment and informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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