When driving in fog lights and wipers become very important tools.
Making sure others can see you is vitally important in misty conditions, you MUST turn on headlights when visibility is poor, or if the fog is particularly bad then use your front fog lights. It isn’t sufficient to run on sidelights alone, even in a light mist these are practically invisible from any distance, and other road users may not have time to react to your approach.
It is not advisable to use main beam headlights in fog. Because of the wide spread of light, a lot of it can be reflected back off the water particles in the mist and this can actually diminish your view even further; use your headlights on dipped beam.
Rear fog lights are also a valuable asset, these can give a much earlier warning to traffic approaching from behind than normal tail-lights, though use them with care.
Rear fog lights are extremely bright and can cause dazzle to following drivers if used at the wrong time. You should only switch them on when visibility is down to less than 100 metres, it’s against the law to use them when visibility is better than this.
Always consider other road users when deciding which lights to use. For example; if you turn on rear fog lights in very thick fog, don’t leave them on in areas where the mist is less dense. Even if it is only for a short while turn them off to prevent dazzle if anyone is behind you. Or if you’re stationary in a traffic queue, once another driver has stopped behind you, switch them off until you get moving again. This is a simple act of courtesy which takes little effort; use your lights with intelligence and adapt them to suit the changing conditions.
In extremely bad fog, as an extra precaution, it may be wise to keep your foot on the brake while waiting at a junction or in a line of traffic. Your brake lights will then serve to make you even more conspicuous, but again be sure to release the pedal once someone has arrived behind you to avoid causing unnecessary dazzle.
Use your windscreen wipers regularly while driving through mist to keep vision as clear as possible. Tiny water droplets will soon build up on the glass, you may not even realise just how much this can restrict your view until a sweep of the wiper blades reveals that the fog wasn’t half as bad as you thought! Keeping the screen warm will also assist in reducing the amount of condensation both inside and out.
This is an excerpt from the Glovebox Guide – Driving at Night & in Bad Weather >>>