Heavy rain reduces visibility, but conditions are not particularly adverse, such as very heavy rain or thick fog. Must the rear fog lamp be switched on for that reason alone?

Correct answer

No; it is not appropriate in these conditions that are not particularly adverse.

No. Article 106 requires appropriate lighting when visibility is significantly reduced but reserves rear fog lighting for particularly adverse conditions, such as thick fog, very heavy rain, heavy snow or dense dust or smoke. Heavy rain must not be treated as automatically qualifying for that lamp. Use it when the particularly adverse conditions exist and switch it off when they end to avoid dazzling.