On an autumn evening near Assen, warm, humid air drifts over the cold meadows beside the road. Within a minute you are driving in thick fog and can see less than 50 metres. There is a car in front of you. What do you do?
Fog lights on, drive more slowly and keep a three-second gap
Fog lights on, drive more slowly and keep a two-second gap
Fog lights on; then others see you and you simply keep your pace
Explanation
False — the usual two seconds are too little in fog like this. With visibility under 50 metres you keep at least three seconds from the vehicle ahead and reduce your speed (Book p.191).