Car lights: which ones to use by day, at night and in tunnels

Dipped-beam headlights and sidelights are compulsory in specific conditions and on certain roads; daytime running lights may be allowed by day where provided. In tunnels and when visibility is reduced, switch on the appropriate lights even if the vehicle has automatic lighting.

By day and on different roads

The Highway Code distinguishes between sidelights, dipped-beam headlights, main-beam headlights, fog lights and daytime running lights. In built-up areas by day, dipped beams are not always required in the same way as on rural roads; on rural roads and motorways, the prescribed lighting must also be on during the day. For some vehicles, daytime running lights may meet the daytime requirement where permitted. Check Article 153 in its current wording and your car’s handbook.

Switch your lights on in a tunnel even during the day, because visibility can fall quickly at the entrance and exit. On some vehicles, the front daytime running lights alone may not switch on the rear lights: check that the rear is illuminated when required. Do not let automatic lighting decide for you in fog or heavy rain; assess the actual visibility and use the manual control when needed.

Use main beam when it will not dazzle other road users, for example on dark stretches with no nearby traffic; switch to dipped beam when meeting or following another vehicle. Front and rear fog lights have specific conditions for use and are not a general substitute for dipped beams. Using them in good visibility can disturb drivers behind or approaching.

• Use the required lights during the day on rural roads and motorways.
• Switch on your vehicle lights in a tunnel and check the rear lights.
• Change from main beam to dipped beam when you might dazzle others.
• Use fog lights only when they are necessary and permitted.

Check the lighting system and automatic settings

Before a journey, check that headlights, indicators, rear lights and brake lights work. If a warning light indicates a fault, consult the handbook and repair it before driving at night or in poor visibility. Clean the lights and windscreen: dirt and clouding reduce effectiveness even when a bulb is on. Incorrectly aimed headlights can dazzle others and should be checked at a garage.

The requirement to switch on headlights does not mean you may drive at any speed: if visibility is reduced, slow down and increase your distance.

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