Driving in adverse weather conditions · Fog
You MUST NOT use front or rear fog lights unless visibility is seriously reduced (see Rule 226) as they dazzle other road users and can obscure your brake lights. You MUST switch them off when visibility improves.
In the Highway Code, MUST and MUST NOT identify legal requirements. Advice using should, should not, do or do not can still be used as evidence in court proceedings under the Traffic Acts to establish liability. The introduction explains this distinction.
The Code reads in order, and each of these names the rule it goes to rather than saying only ‘next’.
The rules the Code files beside this one, in its order.
The other groups in this part of the Code, and the rest of it.