Rear fog lightsUnited Kingdom
An introduction to the traffic rules and road signs of United Kingdom. Learn about driving, road safety and much more in our illustrated book, with answers to frequently asked questions.
For informational purposes only. Always follow official regulations. Some content and images were created with AI assistance.
165. Rear fog lights
Rear fog lights are bright red lights at the rear of a vehicle that make it easier for following road users to see the vehicle when visibility is severely reduced. They are much brighter than normal rear position lights.
Because rear fog lights can dazzle or distract drivers behind, they should only be used in the weather conditions permitted by local traffic rules and should be switched off when visibility improves.
Wikimedia.org • Ehsnils • CC BY-SA
When may rear fog lights be used in Britain?
Use rear fog lights only when visibility is seriously reduced, normally when you cannot see beyond roughly 100 metres. You must switch them off when visibility improves because they can dazzle following drivers.

Traffic rules
United Kingdom