Core: Daytime running lights, dipped beam and full beam

Daytime running lights come on automatically when the engine starts. As soon as you switch on dipped beam, full beam or fog light yourself, the daytime running light must switch off automatically — it is a replacement, not an extra layer of light (Book p.184). Even with automatic lighting, you remain responsible for it happening at the right moment (Book p.183). Dipped beam is mandatory at night, and during the day as soon as visibility is less than 200 metres — for example in rain or fog. If you see many oncoming vehicles with dipped beam during the day, that alone is a signal that bad weather is coming further ahead (Book p.184). You switch on full beam when dipped beam does not give you a good enough overview of the road situation. But three conditions make full beam prohibited: during the day, as soon as another road user (including a pedestrian) approaches you, and as soon as you are following another vehicle at close range (Book p.185). Inside the built-up area, one of those three conditions is almost always true — but that is a practical observation, not a separate rule from the book. Full beam, dipped beam, daytime running lights and sidelights may only emit white or yellow light (Book p.184).