Dense fog

Advice for road users

Travelling in fog can be extremely dangerous. Fog can drift rapidly and is often patchy. Warnings of dense fog are issued when visibility is expected to fall below 200 metres. Severe disruption to transport occurs when the visibility falls below 50 metres.

Make sure you know what to do

During fog

Avoid travel if possible.
Drive very slowly with dipped headlights, full-beam lights reflect off the fog causing a ‘white wall’ effect.
Keep an eye on your speed, fog can give the illusion of moving in slow motion.
Use fog lights, but remember to turn them off when the visibility improves.
Don’t hang on the tail lights of the car in front, rear lights can give a false sense of security.
Watch out for freezing fog which is made of water droplets that freeze on contact with objects such as the pavement, road, car, etc. It can quickly form a layer of ice. Advice for when conditions are icy.

Travel advice produced in association the Highways Agency