The placing of certain signs to indicate the beginning of a restriction, requirement, prohibition or speed limit
8. (1) This direction applies to a sign which is shown in diagram 616, 617, 618, 618.1, 618.2, 618.3, 618.3A, 619, 619.1, 619.2, 620, 620.1, 622.1A, 622.4, 622.5, 622.6, 625.1, 626.2, 627.1, 629, 629.1, 629.2, 629.2A, 632, 642, 646, 663, 663.1, 665, 667, 667.1, 668, 668.1, 670, 672, 674, 951, 952, 953, 953.1, 955, 956 or 957 and which is placed to indicate the point at which a restriction, requirement, prohibition or speed limit applying to traffic on a road (in this direction called “the relevant road”) begins.
(2) Subject to paragraphs (3) and (4), a sign to which this direction applies shall be placed on the relevant road at or as near as practicable to the point referred to in paragraph (1)—
(a)where the road has only one carriageway, on each side of the carriageway of the road; or
(b)where the road has more than one carriageway, on each side of each carriageway in relation to which the restriction, requirement, prohibition or speed limit begins.
(3) Where the relevant road has one carriageway, signs to which this direction applies need only be placed on one side of the relevant road to indicate the point at which a restriction, requirement, prohibition (but not a speed limit) begins—
(a)where the restriction, requirement or prohibition applies only to traffic on one side of the relevant road; or
(b)at a junction where—
(i)traffic proceeding on another road on which it is permitted to proceed only in one direction turns into the relevant road; or
(ii)the relevant road is less than 5 metres wide.
(4) Where a length of road which passes under or through a bridge, tunnel or other structure is subject to a prohibition on vehicles exceeding a particular height, the sign shown in diagram 629.2 or 629.2A may be placed on the bridge, tunnel or other structure to indicate the prohibition in addition to or instead of the signs placed as required by paragraph (2).