With news that freezing fog is set to move in across the East Midlands, East Anglia, London and the South East, northwest England, southwest England, Wales and the West Midlands, the Met Office has issued a yellow weather warning in affected areas.
Visibility may be reduced to less than 100m in some areas, the UK's national weather service says.
Disruptions are likely to bus and train services, while some flights have been cancelled by British Airways.
1. Only travel if you need to
The simplest way to eliminate the possibility of a collision or a breakdown is not to drive unless it is absolutely necessary. It may be better to wait until the fog clears.
Switch on your dipped beams and make sure the lights are working front and rear, on both sides. Double-check your lights are set to the dipped beam setting. This will maximise what you can see, and help ensure other road users can see you. If you have automatic headlamps, ensure they are on - or better yet, override the auto setting and turn them on manually. Avoid using full beam as this can reflect off the fog and make it harder for you to see. If you see the small blue headlight icon lit up on your dashboard, your full beams are on; turn them off.
Make sure you know how to turn on your rear fog lamps, indicated by an orange lamp-shaped symbol. These will only function when headlights are switched on. Fog lamps should only be turned on if visibility drops below 100m. If you cannot see the rear lights of the vehicle in front, it probably means you should turn on your fog lamps. Your car may also have front fog lamps, indicated by a green lamp-shaped icon featuring sloping straight lines and a wavy line. Be sure to turn off your fog lights when the fog clears, or you will dazzle other road users.
In foggy weather, condensation can form quickly without you noticing. Using your heaters should prevent this. In addition, you should switch on your rear window's heating system. If your car is equipped with a heated front windscreen, turn it on too.
Your hearing can prove invaluable in detecting nearby traffic, so turn off any music. Winding down your window as you near a junction will also help identify any approaching vehicles.
Many a road accident has occurred in foggy, icy conditions because traffic has been too bunched up. Give yourself more time to stop by leaving a larger gap between your vehicle and the one in front. If you are being followed too closely, stay calm and let them pass if it's safe to do so.
The nature of fog means you can't easily see the car in front. Don't assume that if it looks clear, it is. Keep your speed down and give yourself more time to react as necessary.
With this in mind, it is even more important to drive cautiously and slowly.