Understanding Car Lights

Understanding Car Lights

Lights in a car are essential to:

  • allow a driver to see clearly ahead of them
  • allow a vehicle to be seen 
  • inform other road users of a driver’s intentions

Therefore, it’s important as a driver that you know what lights are available on your car and when they should be used; and it’s vital that lights are checked regularly and kept in good working order. This blog will help you understand more. 

Dipped headlights 

This is the most used type of light. 

They are designed to dip downwards towards the road so that they don’t dazzle people. 

The Highway Code says you must use headlights when visibility is seriously reduced.

This means they must be turned on at night and during bad weather. 

You must make sure both your dipped headlights are working properly. You need to see clearly when driving at night-time, but also you want to be seen by other road users. 

Tail Lights / Rear Lights

Your taillights are at the back of your car, they will turn on when you turn on your headlights.

This means that when you turn your headlights on, your headlights and tail lights are activated.

Running lights 

More modern cars will have daytime running lights. 

These lights are at the front of a car only and they are on whenever the engine is turned on.

They are fairly dim and don’t illuminate the road ahead.

The purpose of running lights is to increase the visibility of your car so the other drivers can see you.

Full Beam Headlights 

These are the brightest type of light in your car.

They are angled higher than dipped headlights so that you can see much more of the road ahead of you. 

You should only ever use full beam headlights when you’re travelling on unlit roads at night-time. Using these lights at other times can dazzle other road users and cause an accident.

You will need to turn these lights off when meeting oncoming traffic, pedestrians or cyclists 

When you’re driving behind another vehicle they should be turned off, and if a driver is overtaking you, turn them off as they pass by your car.  

Fog Lights 

These lights are designed to cut through fog and mist. 

You should only use fog lights from visibility is below 100 metres.

With your fog lights on you will see the road ahead more clearly and other road users will be able to see you easier as well.

As soon as visibility improves you must switch your fog lights off again. If you leave them on you can dazzle other road users.


Indicators are there so you can let other road users know what you intend to do. 

When you turn your left indicator on, a light will flash at the front and back of your car on the left-hand side. 

When you turn your right indicator on, a light will flash at the front and back of your car on the right-hand side 

You should use indicators in good time and appropriately.

Signal to let other road users know that you are:

  • turning into a new road 
  • changing lane 
  • moving away or pulling up (only if other road users are around to benefit)

Hazard Warning Lights 

Hazard lights are your indicators. When you turn your hazard warning lights on all four indicators will flash.

You should only use your hazard warning lights in certain situations:

  • use hazard warning lights if your vehicle is stationary, to warn others that you’re causing a temporary obstruction. This may happen if you have an accident or your breakdown 
  • you can also use your hazard lights if you’re on a motorway or dual carriageway, and there is an obstruction ahead that you want to warn drivers behind you. You should only use them for long enough for the drivers behind to notice, then turn them off. 

Note: Hazard warning lights or any other lights should not be used to thank other motorists, show annoyance, tell somebody you’re giving way, to say hello to someone you know, or for any other reason than the reasons given above.  

Parking Lights or Side Lights

These are not as bright as headlights and some drivers use them to help themselves be seen when it’s not quite dark enough for dipped headlights.

The Highway Code says that all vehicles must display parking lights when parked on a road or layby with a speed limit over 30 mph. 

They are designed to be left on for long periods when you leave the car, so they won’t flatten your battery.

Brake Lights

Brake lights are at the back of your car. They are bright red and will light up as soon as you press the brake pedal. They are there to let the road user behind know that you are slowing down. 

Your brake lights must be clean and working at all times. If your brake lights aren’t working the driver behind may not know of your intentions to slow or stop and could therefore collide into the back of you.

Check your brake lights by pressing the brake pedal and seeing a reflection in a window or garage door for example, or you can get someone to stand behind the car while you apply the brakes.

You should try not to press your brake pedal unnecessarily. Each time you press your brake pedal your brake lights light up which can be distracting for drivers behind. If you’re in a traffic queue aim to avoid using your brakes when you’ve stopped the car, instead apply your handbrake to avoid dazzling other road users.

Keeping lights clean and in good working order will help to keep yourself, your passengers and other road users safe. Familiarise yourself with the various lights in your car and practice using them when it’s safe to do so. That way, when you need to use them quickly, for example, you need to flash your headlights, you know how to do it automatically. 

We hope you have found this blog useful. There are many more in the series to keep you informed and up to date. Do check them out. 

Theory Test Course has all the latest DVSA practise theory tests. Before practising the questions, the course has worksheets to fill in, video tutorials to watch, fact lists to listen to, and much more. If you want to pass your theory test first time, go to: 

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