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Car lights: learn the rules

  • Car lights: learn the rules

Each light on your car serves its own vital purpose, and failure to use them correctly or neglect to change the bulbs when they go out could get you into trouble. Are you up to speed with what lights your car has and when they should be used? Let us enLIGHTen you… 

Headlights and tail lights 

Headlights are the main event on the front of your car, and they’re what you’ll see by in the dark. They provide greater visibility than sidelights (more on those later), and have two settings: dipped beam and main beam…

Dipped beam

These are the most commonly used out on the roads, so-called because they’re angled down towards the road and not straight ahead. Main beam headlights are dazzling to oncoming road users and anyone you’re following, whereas dipped beam offers adequate visibility without blinding other motorists. 

The Highway Code states that you ‘must use dipped beam headlights when visibility is seriously reduced’; that means you are able to see less than 100m in front of you without them, such as in the dark or in bad weather. 

Full beam 

As the brightest setting, main beam is reserved for roads that are pretty much pitch black at night. 

The Highway Code says that you ‘must not use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders’. Therefore, when you meet road users, whether oncoming or in convoy, you must switch back to dipped beam so as not to dazzle them. 

Tail lights

These lights on the rear of your vehicle operate at the same time as your dipped beam, and have just the one setting, so no need to adjust them according to the road conditions. These lights are red, to alert other road users behind you to your presence. 

Fog lights

These powerful illuminations cut through poor visibility caused by fog. Fog simply reflects the light from headlights back at you, which is no good, so fog lights are situated on the front of your car in order for you to move forward, and at the rear so that you can be seen by motorists behind you. 

Fog lights should only be used when visibility drops below 100m due to mist or fog, and should be turned off when visibility improves. 


Otherwise known as parking lights, you’ll find these bulbs within the main headlight units, and they’re designed to make your car visible when you’re stopped. In fact, they’re a requirement when you’re parked on a road (or an adjoining layby) where the speed limit is over 30MPH. 

If the speed limit is 30MPH or under and you’re facing in the same direction as the traffic, you’re against the kerb, and you’re at least 10 metres from a junction, you don’t need to use them.

There’s no need to panic about your battery if you need to leave your parking lights on for a little while; they’re designed for this, and therefore won’t be a drain on it. 

Brake lights 

We’re pretty sure you can guess the consequences if those travelling behind you didn’t know that you were pressing the brake - it would be a recipe for an accident. These only come on at the rear of your vehicle when the brake pedal is engaged, so that everyone can see when you are slowing down and react accordingly. 

Not having brake lights visible comes with penalties, as it’s a safety concern. So if you’re found to have a brake light out or if it’s too dirty to be seen, you could be facing: 

  • A verbal warning given by police at the roadside
  • A fixed penalty notice, which will include a £60 fine and three points on your licence
  • A Vehicle Defect Rectification Notice, which is 14-day order to fix the fault and provide proof of the fix


Coloured orange and located at the four corners of your car, indicators do just that; they indicate to other road users where you’re going, whether it’s turning off, or moving lanes. 

As with brake lights, not using your indicators, or having ones that don’t work can be a serious safety issue, so whilst there’s no specific law that refers to indicators, failure to display them correctly can be seen as careless and inconsiderate driving, or driving without due care and attention, both of which are offences.

Hazard warning lights 

Imagine all your indicators flashing at once; that’s what happens when you press your hazard warning light button. 

The list of individual reasons why you’d use these is long, but in general, it’s when you need to alert others that all is not as it should be; you’re slowing down for a hazard, there’s a fault with your car that prevents you keeping up with the flow of traffic, you’re broken down at the side of the road or you’re temporarily parked where you shouldn’t be. 

Daytime running lights 

Vehicles manufactured since 2011 have daytime running lights built in, which operate entirely automatically when the engine starts up and the headlights aren’t on. They’re only found at the front of the vehicle. 

Number plate lights

It’s a legal requirement to have your number plate adequately illuminated, as they’re your vehicle’s identification. In low light, this relies on the presence of working lights above both the front and rear number plate, so if these lights are out, your car will fail its MOT, and you could be pulled over by police.