Auto advice: Everything you need to know about your car’s headlights and fog lamps

Published on 27 November, 2022

Overview

What are daytime running lights (DRLs) and when should I use them?

Daytime running lights are lights that switch on automatically when the engine starts and have been compulsory on all cars built since 2011. Under EU law, DRLs are only required on the front of the car and do not illuminate the rear so aren’t suitable when driving in the dark. They’re designed to help other road users see your car in daylight.​

When should I use dipped or full beam headlights?

Dipped lights are used at night and during bad weather, They’re the brightest lights that can be used without dazzling other road users. When the road is clear, switch to full-beam headlights at night. Always remember to switch back to dipped headlights when you meet oncoming traffic including cyclists or pedestrians and when driving behind another vehicle or in a built-up/residential area with good street lighting.

What lights should I use when there’s fog?

Turn your dipped headlights on but never use the full-beam headlamps in fog as this will only reflect the light back at you, and actually reduce rather than improve visibility. Always remember to switch on your fog lights when you cannot see more than 100m in front of the vehicle — that’s roughly the length of a football pitch. Fog lights are designed for use when visibility is very low due to dense fog or falling snow and are positioned to illuminate the road and make you visible to other drivers.​

How do I know which ones are my fog lights?

The dashboard symbol for fog lights is a lamp with three diagonal lines intersected with a wavy vertical line. If the wavy line is to the right, then this refers to the rear lights; if it is to the left of the lamp, it refers to the front fog lights. Generally the indicator light for the front fog lights is green and amber for the rear fog lights.

Remember to turn your fog lights off when you’re out of the fog as otherwise you’ll dazzle other motorists. Your brake lights can also be obscured by rear fog lights so other drivers may not know when you’re braking. This is why it’s illegal to use fog lights when there’s no dense fog or falling snow.

Top tip: Hazard lights are intended to warn other road users of a danger ahead so they should only be used when your vehicle is stationary or to indicate to other drivers there is an obstruction up ahead.

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