How to use your headlights in winter driving

  • As the UK is plunged into darkness, lights become essential
  • Learn which lights your car has, and when to use them
  • Appropriate illumination for comfort and safety

Audi RS5 DRL

Britain's driving conditions have altered significantly since the first guidelines for lighting were laid down in the Highway Code. Terms like sidelights and parking lights, or dim-dip headlights, have fallen by the wayside as modern cars feature automatic lighting, powerful LED day-running light signatures and brake lights with near-instantaneous reaction and variable brightness.

Even with all this technology, lighting is still best left to the car's main control system - you, the driver.

You can judge conditions based on more than just a measurement of ambient light, and you can see the effect vehicle lighting has on the environment you drive in; if in doubt, look at the cars round you. If you think their lights are inadequate, consider the lights your car is showing to other road users, particularly if your car is a dark shade.

All new cars have a basic set of lights, to which additional functions may be added.

  • Head and tail lights, with high and low beams for the front
  • Front parking lights, a low power marker light.
  • Brake lights at the rear, on both sides of the car and a third central one
  • Indicators, front, rear and on the side - often on the mirrors
  • Hazard lights, causing all indicators to flash at once
  • A rear fog light, which can be central or on the driver's side of the car
  • Rear number plate lights
  • Day running lights, which may be a low-power headlight, or an additional signature light at the front of the vehicle

Additional lighting may include extra lights for high beams, front fog lights, cornering lights (often incorporated in the fog lights) and a second rear foglight to make the rear of the car safe in RHD or LHD countries.

More advanced systems will have adaptive headlights, which use multiple beams to light more of the road without dazzling other road users, and provide a wider, directional spread of light for cornering.

The Highway Code gives clear definitions on when lights should be used. In areas of street lighting, it is permissible to use 'sidelights' or parking lights, particularly on cars equipped with dim-dip headlights. The assumption here is that these lights are visible to other road users and the street lighting provides enough visibility to the driver for the permitted speed.

Twingo 1 sidelights only

In all other areas, legally you are required to switch on your headlights half an hour after sunset, and may switch them off half an hour before sunrise. That's the legal definition of night; however, common sense and the Highway Code both agree that visibility is key. If you cannot see 200m in front clearly and consistently, switch on your headlights.

Twingo 1 headlights on

When should I use foglights?

Front foglights are designed with one purpose in mind - to look cool.

At last, that's what many drivers seem to think - but that's not what they're for. Casting a wide, low and short spread of light, they're intended to shine under fog and illuminate kerbside and road markings in significantly reduced visibility.

Twingo 1 Front Foglights

On public highways, they serve no other purpose - and in wet conditions they're almost dangerous, increasing the amount of dazzling light reflected off the road - without providing any benefit to the driver.

Rear foglights are similarly intended only for severely reduced visibility. If you cannot see the tail lights of the car in front of you easily - then you can safely assume that cars behind will be unable to see your lights untul they're equally close to you.

100m is a good benchmark as well as a legal definition - that's roughly the distance from the final countdown marker to an exit sliproad. Remember, though, that in lines of traffic cars close to you will be dazzled by your foglights. Ideally they should be off if a car is following you close enough that you can see their headlights clearly.

Brake lights can dazzle

The Highway Code is similarly clear on the use of brakelights. When stopped in a queue or at lights, you should put the car in neutral and engage the parking brake/handbrake, then release the brake pedal. As long as your foot is on the pedal, the brake lights are lit - dazzling and distracting cars behind you.

Again, common sense does suggest times when brake lights are useful when stationary - such as a rural road with temporary traffic lights - but the moment a car is stopped behind you; be legal, be courteous, be kind.

Cars with auto-hold handbrakes, or adaptive cruise control, will show their brake lights when stopped unless you engage the parking brake (and put them in neutral or park when applicable), so drivers sitting with their brake lihgts on might not be doing so just to dazzle you!

Indicators are even more important in winter

You may be able to see around your car well enough to safely change lanes – but in reduced visibility, other drivers may not see you early enough to react if you do so without signalling. Even if you think there's no traffic to see it, in poor weather or at night it's worth using the indicators -

Day running lights - a false sense of security

Modern cars often have illuminated dashboards whether lights are on or off, and LED day running lights can provide a dim, but apparent light ahead of the car. However, not all systems illuminate the tail lights, meaning you're dangerously invisible.

Most manufacturers offer automatic headlights as an option - many cars feature them as standard equipment now - but even with those fitted some weather and light conditions may fool the system. If in doubt, switch headlights on.

Audi RS5 Tail Light

Switching on when it's bright, too

Lights help visibility in bright sunlight conditions, too. In low winter sun, it's worth switching headlights on to be more visible when the sun is behind you, as oncoming drivers may be dazzled and your shadowed car hard to spot.

Unless your car is bright neon coloured, it can blend into the scenery surprisingly well now so many cars have bright LEDs on all the time, If you don't have day running lights, it's worth having dipped headlights on no matter what the weather..

Addtional lights - LEDs, driving and foglights

On older cars it's worth investing in front foglights if you live in an area affected by frequent mist or fog. These may be available as third party units, or manufacturer accessories, and should be wired in so they're available when sidelights or headlights are on.

You can also add auxilliary spotlights/driving lights. These should meet all current regulations for output, and be positioned in line with the headlights or lower. High power, roof mounted lights are for off-road use only.

LED day running lights are a popular accessory. Rather than wiring them to the ignition, connect them to the car sidelight position. This will ensure the bright front lighting is backed up by taillights. LED bulbs are also available as upgrades for classic cars, and are worth investing in particularly for brake and signals.