A night drive over the Afsluitdijk in heavy snowfall, visibility roughly 30 metres. An hour later, further on near Assen, the snow has turned into pouring rain, visibility roughly 35 metres. What is correct?

In both cases the rear fog light may be on, because visibility is below 50 metres in both
✓ During the snowfall the rear fog light may be on, during the rain it may not
In neither case may the rear fog light be on, because the weather cause does not count

Correct answer: During the snowfall the rear fog light may be on, during the rain it may not

Explanation

False

The visibility figure alone is not enough; the cause must be fog or snowfall. In rain the rear fog light stays off, even below 50 m
The cause does matter: during heavy snowfall with visibility <50 m the rear fog light may go on (Book p.191); only in rain it may not.