Whether it’s thick fog, rain, mist or cloud, driving in poor visibility can be nerve-wracking.
Here’s our guide to when to use different car lights. It’ll help you see and be seen in poor driving conditions, as well as avoid a fine.
In this article
Types of car lights
Looking after your car lights
What are dipped headlights?
Dipped beam headlights are your go-to for driving at night and in poor visibility. These headlights are brighter than sidelights and less bright than full beam.
- They’re also know as low beam headlights.
- They’re angled downwards so you can pass other road users without dazzling them.
- They give better visibility of the road and help other drivers see your car better than side lights.
Make sure that your dipped lights are at the right angle. You could get a £50 Fixed Penalty Notice if your dipped beam is angled incorrectly and you dazzle other drivers.
Find out how to correctly angle your lights.
When to use dipped headlights
You should use dipped beam headlights at all times when driving at night (unless you need to switch to full beam).
You can also use dipped headlights during the day. The Highway Code advises cars to use headlights whenever visibility's seriously reduced. It also recommends headlights during the day for motorbikes so they can be seen more easily.
What are full beam headlights?
Full beam are your brightest headlights. They’re brighter than sidelights and dipped headlights.
- They can be called full beam, main beam or high beam headlights.
- They’re angled higher than dipped headlights so they can light up more of the road.
- They’re best for driving along unlit roads at night.
When to use full beam
Full beam headlights will help you see better than dipped beam on unlit roads. But you must remember to switch back to dipped lights every time you see a car coming in the opposite direction.
You must also dip your lights if you see anyone in front of you travelling in the same direction. If you leave your main beam on, you’ll dazzle other drivers when they look in their rear-view or wing mirrors.
The Highway Code says, ‘don’t use any lights in a way which would cause dazzle or discomfort to other road users’.
Flashing your headlights
Headlight flashing is when you briefly flick your headlights from dipped beam to full beam.
The Highway Code says:
- Only flash your headlights to let other road users know you're there.
- You’re not supposed to flash your lights to send any other message - even to warn others of hazards in the road.
- You shouldn’t flash your lights to intimidate road users.
- Never assume that someone flashing their headlights means its safe for you to go, for example at a junction.
- Use your own judgement and proceed carefully.
You can be fined for headlight flashing if you’re considered to be ‘misusing your lights’.
If other drivers keep flashing you, there may be something visibly wrong with your car. You could have a broken bulb, you may have left your main beam or fog lights on by mistake, or you may have forgotten to switch your headlights on.
Daytime running lights
What are daytime running lights?
All modern cars now come with daytime running lights (DRLs). These are bright lights, often LED, that help you to be seen during the day.
- They should come on automatically when you start your car.
- They’re too bright for night driving as they could dazzle other road users.
- DRLs should switch off or dim when you turn on your headlights.
When to use daytime running lights
You should use daytime running lights throughout daytime hours. They’ll come on automatically so you won’t need to remember to turn them on or off. Just make sure you don’t use them instead of dipped beam at night.
What are car sidelights?
Sidelights are the least bright of the lights at the front of your car.
- They’re dimmer than dipped headlights and full beam lights.
- Sidelights can be used when visibility is slightly reduced.
When to use car sidelights
According to the Highway Code, you need to use car sidelights between sunset and sunrise.
Drivers can use them to make their car more visible to other drivers when it’s not dark enough to use headlights. But you won’t need sidelights if your car has daytime running lights instead.
What are hazard lights?
Hazard lights are the blinking yellow lights on the sides of your car. They’re used to warn other road users.
- Hazard lights are there for emergencies, like if you’ve broken down.
- You can switch them on using the warning triangle button on your dashboard.
When to use hazard lights
The Highway code says:
- You can use hazard warning lights when your car’s stationary.
- They’ll warn others that you're temporarily obstructing traffic.
- Don’t use them as an excuse for illegal or dangerous parking.
- You shouldn't use hazard lights when being towed.
You can use hazard lights if you’ve broken down on a motorway (or unrestricted dual carriageway) or to warn drivers behind you of a hazard or obstruction ahead. But remember to switch them off once your warning's been seen.
What are fog lights?
Car fog lights are front or rear lights that help you to see the road ahead and help other drivers see you when it’s very foggy or misty.
- They're also called fog lamps.
- Front fog lights help you to see the road ahead, lighting the road surface while minimising glare and reflection from the fog.
- A rear fog light helps other drivers see your car when visibility’s poor.
When to use fog lights
It’s not the law to use fog lights, but it’s sensible to switch them on when visibility's really bad. It’ll help other cars see you.
Rear fog lights are the most important, so other drivers can see you as they approach from behind.
Remember to turn car fog lights off once the fog clears. Rear fog lights can obscure your brake lights and dazzle drivers behind if you use them when visibility’s clear.
What are brake lights?
Brake lights are the red lights at the rear of your vehicle.
- Car brake lights come on when you press the foot brake pedal, or
- In electric cars that use regenerative braking, the brake lights will come on automatically when deceleration reaches a certain level.
- Brake lights warn other road users that you’re slowing down.
When to use brake lights
You should use the foot brake to slow down rather than just taking your foot off the accelerator. That way, other road users behind you will be warned by your brake lights that you’re slowing down.
If you’re sitting in a queue of traffic or waiting at traffic lights, put your handbrake on. If you sit with your foot on the brake, your brake lights can dazzle road users behind you.
Looking after your car lights
Checking car lights
You don’t want to drive around with 1 headlight and risk a fine. Check all your car lights at least once a fortnight, remembering number plate lights and fog lights.
There’s a few ways you can check your lights are working:
- Ask a friend to help.
- Check reflections in a window.
- Check front and rear lights by driving or reversing up close to a wall.
Cleaning car lights
Even if your lights are working fine, they'll need a regular clean. You can clean your car lights and number plate at the same time.
- If winter grime has built up quickly, you can easily remove it if you stop for a break using screwed up newspaper or a rag.
- If you have more time, car shampoo and water will do a better job of removing stubborn dirt, bird poo or dead insects.
- If your car lights are clouding due to oxidisation, there are specialist products that can help.
Adjusting car lights
To drive safely, it’s important to make sure that your car headlights are adjusted correctly. If headlights are aimed too low, it’ll limit your field of vision and you won’t be able to see as well driving in the dark. If they're aimed too high, you’ll dazzle other road users as you drive.
Your headlights could be adjusted incorrectly if:
- You’re carrying a heavy load.
- There’s a problem with your suspension.
- Hitting a road hazard has caused your lights to shift.
You can check the adjustment and aim of your lights yourself but this requires a completely level surface. Check your vehicle handbook for advice on adjusting your lights or take your car to a garage if you’re in doubt.
MOTs and car lights
As part of the MOT test, lights are checked for:
- Condition - They’ll look for any defects.
- Operation - They’ll check the lights work properly.
- Headlamp aim - They can dazzle if they’re aimed too high.
- Cleanliness - Nothing should change the light’s beam or colour.
- Security - Lights should be securely fitted.
- Self-levelling - Some HID or LED lights aim using a sensor.
The tester also checks that the full-beam warning light on the dashboard is working.
Check your lights before taking the car for its MOT. Replacement bulbs aren't expensive and some can be changed easily. Just check your car’s handbook. If the lights you’re confident doing it, a garage should be able to help.
Fines for faulty car lights
You can be issued a £50 Fixed Penalty Notice for 'lighting offences' like a broken brake light.
The police can give you a 'vehicle defect rectification notice' instead, if they wish. This means you have to get it repaired as soon as possible and provide proof (e.g. a mechanic receipt) to the police within 14 days.