Car lights and bulbs: the complete guide

The different types of car lights

In this section, our experts will answer some of the common questions asked about car lights, starting at the front of the car.

What are the side lights on a car?

The side lights, or sidelights, can be used when visibility is slightly reduced, but not to the point when dipped headlights are necessary. In recent years, these have been replaced on new cars by daytime running lights (DRLs), which are illuminated as soon as the vehicle’s ignition is switched on, and are only extinguished when the dipped headlights are activated and, sometimes, when you turn on an indicator.


What are dipped headlights?

The dipped headlights should be used when visibility is compromised by the onset of darkness, or by adverse weather such as rain, fog or snow.

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What are a car’s full beams?

Full-beam headlights are the brightest lights at the front of the car, and should be used as above and when there is no other road user ahead of you or approaching.

What are foglights and when should they be used?

Some cars, but not all, have a pair of front foglights. These are designed to spread the light beam so it illuminates the edges of the road closer to the front of the car, making it easier to see the kerb in thick fog. In modern cars, they are sometimes used to mimic the effect of advanced directional headlights – when the steering wheel is turned, the foglight for that side of the car will illuminate to light up the road in the direction that you are turning.

What are indicators?

Finally, at the front there will be two orange indicators; these flash on either the left or right side to let other road users know that you intend to make a turn. You will often find secondary indicators on the front wings or door mirrors.

How have car lights changed?

Headlight technology is improving all the time, and has moved a long way from the dim bulbs (or even candles!) of old. Many cars now have bulbs filled with xenon gas, which is much brighter than traditional bulbs, and is also less tiring to follow for the driver’s eyes. However, some manufacturers have moved on, and now offer LED headlights, which are brighter and longer-lasting still, yet which consume less energy. Finally, some car makers are now offering laser headlights, which promise yet another step in brightness and efficiency.

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What lights are at the rear of a car?

At the back of a car are bright red tail lights, which are illuminated when the headlights or sidelights/DRLs are on. The brake lights are the same red as the tail lights, but are much, much brighter and are only illuminated when you press the brake pedal.

Again, a rear foglight helps your car to be seen in fog and heavy rain, while a white reversing light signals to others that you intend to reverse, and helps you to see behind.

As with front lights, traditional bulbs in the rear lights are being replaced with LED technology, which is brighter, more efficient and more reliable.