45.—(1) A traffic sign for conveying the warning specified in paragraph (2) to vehicular traffic on a motorway or an all-purpose dual carriageway road shall be a light signal of the size, colour and type shown in diagram 6023.
(2) The warning conveyed by the light signal shall be that—
(a)there is a hazard ahead on the motorway or all-purpose dual carriageway road; and
(b)drivers should drive at a speed which does not exceed 30 mph until they are certain that the hazard has been passed or removed.
(3) When the light signal prescribed by this regulation is operated, each lamp shall show an intermittent amber light at a rate of flashing of not less than 60 nor more than 90 flashes per minute and in such a manner that one light is always shown when the other light is not shown.