How much can you see in fog?

Move the fog slider, then try the lights.

Driver’s-eye view of a road in fog A UK road with distance references at 25, 50, 100 and 200 metres. Distant objects fade as fog increases. Main beam creates glare in fog. A separate inset shows your rear lights from behind.

Illustrative view · reference distances from your car

Post25 mClearCar50 mClearSign100 mClearTree200 mClear
ClearVery dense
Headlights
Fog lights

Highway Code and this illustration

Headlights must be used when visibility is seriously reduced, generally when you cannot see beyond 100 metres. Front or rear fog lights may also be used then, but must be switched off when visibility improves. Stop well within the distance you can see clearly. Rules 226 and 235–236.

Main beam can reflect light back in fog: Met Office fog guidance.

Distances mark objects in this drawing. Fog, light beams and glare are illustrative, not measured visibility or headlamp performance. Front fog lights illuminate nearby road; rear fog lights help others see you. They do not remove fog. Vehicle lighting arrangements vary.