Dipped headlights explained: what are dipped beams and when to use them

Cars have become smarter and more sophisticated in recent years, with lots of tech now controlled automatically by a cutting-edge combination of sensors and computers. One such system found in most new cars is an ‘auto’ setting for the headlights. This will turn on your headlights in the dark without any input from the driver.

However, not all cars feature this technology and drivers are still responsible for switching between full beam and dipped beam as necessary. But when should we use dipped headlights?

To help you drive safely in the dark, we have created a guide to using dipped beam headlights. Read on to find out when to use dipped beams, and what other headlight settings are used for.

What are dipped headlights?

Dipped beam is the standard setting for headlights at night, while full or high beam is used to increase visibility when roads are empty and unlit. Most cars also feature sidelights and, since 2011, nearly all cars also have daytime running lights (DRLs), which we'll discuss shortly. To avoid dazzling or blinding other drivers, dipped beam lights need to be pointed below the eye level of other road users, and this is checked as part of a vehicle’s MoT. 

What are adaptive and matrix LED headlights?

According to the Highway Code, you should turn on your sidelights and rear registration plate lights between sunset and sunrise on roads with street lighting and built-up areas. Dipped beam headlights are required on all other roads at night, defined as the period from half an hour before sunset to half an hour after sunrise.

When should I use dipped headlights?

As per The Highway Code, dipped beam headlights should be used ‘at night in built-up areas and in dull daytime weather, to ensure you can be seen’. While this may seem like it contradicts the recommendation to use sidelights at night in built-up areas, the use of sidelights should be considered as merely the minimum legal requirement – dipped beam headlights are the best choice whenever it’s dark or visibility is reduced.

When it’s raining hard enough to require the continual use of your wipers, it’s also recommended that you turn on your dipped headlights regardless of whether it’s dark or not. This is because heavy rain reduces visibility and can obscure you from other drivers – turning on your dipped headlights will allow other drivers to spot you more easily. Headlights should also be used when passing through a long tunnel, and you will often see this signposted as you enter one. If it’s so dark that you can’t see your dashboard’s dials clearly, this is a sign that you should turn your headlights on.

Many modern cars have an ‘auto’ setting for their lights that switch on and off when the car’s sensors think they should be illuminated, but there can still be occasions when manual input from the driver is required. It’s best practice to keep your lights switched to this setting rather than keeping the switch in the off position. At least this way the car’s headlights will illuminate when it gets dark.

However, the Highway Code also notes that dipped beam headlights should also be used when ‘visibility is seriously reduced’ such as in heavy rain or fog. In these situations, it’s quite possible that your car’s auto lights function will not detect that dipped beam headlights are required, which is why you should always be prepared to manually override the auto function.

In these types of weather events, you may be tempted to use your main beam headlights, but this may actually reduce your visibility. Rain and fog particles in the air can reflect the light from the main beam headlights back at the driver, potentially dazzling them. As the dipped beam headlights point towards the ground, visibility should be improved without any unwanted dazzling.

Of course, you must also use the car’s fog lights when you cannot see for more than 100 metres, but you need to remember to switch them off when visibility increases once again; it’s an offence to drive with fog lights on in good visibility as they may dazzle other road users.

What are daytime running lights (DRLs)?

Confusion can sometimes arise thanks to the advent of daytime running lights (DRLs). These are permanently illuminated on cars registered since 2011 (and before on some makes) and cannot be switched off while the car is running – they will illuminate even when the car’s light switch is in the off position. Crucially, DRLs only illuminate the front lights, so when it becomes dark your rear lights will usually remain unilluminated making your car very hard to see from the rear.

DRLs are only designed to make your car easier to spot during daylight hours, and they won’t provide any illumination of the road ahead, so must never be used instead of headlights once darkness falls.

What are main beam headlights?

Main-beam headlights should only be used when on roads away from built-up areas and only when there are no other vehicles or road users (including pedestrians and cyclists) in front of you, otherwise they will be dazzled by your main beam lights. When main beam lights are being used there will be a blue tell-tale light illuminated in your car’s dashboard to remind you they are on. You should turn them down to dipped whenever another vehicle or road user is in sight.

It goes without saying that your lights should be in good condition – check your car regularly to ensure all bulbs illuminate – not just your headlights, but all the lights. The light lenses should also be clean, as dirty lights can seriously reduce their effectiveness.

Dipped beam headlights: a final checklist:

• As a minimum, turn on sidelights when it’s dark in built-up areas
• Best practice is to use dipped beam lights at all times when it’s dark
• Use dipped beam lights when ‘visibility is seriously reduced’
• Fog lights can be used when visibility is reduced to less than 100m
• Use your car’s auto light setting but be prepared to switch dipped beam lights on if required
• Daytime running lights are not a substitute for dipped beam headlights
• Only use full-beam headlights if the road ahead is clear of other road users

Read our guide to parking lights and how they work here.