In which of these situations do the rules permit front fog lights because of visibility conditions?

Correct answer

In fog or heavy rain substantially reducing visibility.

Fog or heavy rain substantially reducing visibility. Article 106 allows front fog, dipped beam or main beam in those conditions; it does not always require front fog as the sole choice. It is also allowed on narrow sections with signed successive bends meeting that provision. Front fog lights may be combined with other lighting subject to applicable rules and without dazzling; main beam in fog often causes reflection. A tunnel or additional lane alone does not authorise front fog lights without the required conditions.