(a) may be placed only in connection with works involving—
(i) an alteration in the layout of the carriageway of a road or level crossing; or
(ii) the placing, removal or alteration of traffic signs on or near a road or at a level crossing; and
(b) may be retained not later than the end of the period of 3 months beginning with completion of those works.
(2) The sign shown in diagram 7032—
(a) may be placed only to indicate the point at which a recently imposed speed limit of 30 mph begins on a road—
(i) on which there is a system of street or carriageway lighting furnished by lamps lit by electricity placed not more than 183 metres apart in England and Wales or not more than 185 metres apart in Scotland; and
(ii) which had previously been subject to a higher speed limit;
(b) shall be placed as near as practicable to that point;
(c) shall not be placed unless that point could not otherwise be indicated in accordance with these Directions;
(d) may be placed only during the period of 6 months beginning with the day on which the 30 mph speed limit comes into force; and
(e) shall not be retained after the end of that period.
38.—(1) No sign of the kind referred to in regulation 53 may be retained at any place for more than 6 months (or in the case of a sign of the kind referred to in regulation 53(1)(d) for more than 2 years) or such longer period as the Secretary of State may approve after the placing of the sign there or in any event after the sign has ceased to be needed at that place.
(2) The sign shown in diagram 2701 or 2701.1 may be retained on or near a road for not more than six months after completion of the housing development to which it refers.
39.—(1) The sign shown in diagram 7023 or 7024 may be placed on or near a road only where—
(a) one-way working is necessary along a length of road because part of the width of the carriageway has been temporarily closed to traffic; and
(b) either—
(i) there is no junction with another road along that length; or
(ii) the traffic authority has given express written approval to the placing of the sign in relation to a length of road having a junction with another road.
(2) The sign shown in diagram 543 may be placed in combination with the plate shown in diagram 7030 only on or near a road on which convoy working is in operation and indicated by one or more of the signs shown in diagrams 7025, 7026, 7027, 7028 and 7029.
(3) The sign shown in diagram—
(a) 554 when varied to "Flood" or "No smoking";
(b) 554.2 when placed in conjunction with the plate shown in diagram 554.3; or
(c) 562 when placed in combination with the plate shown in diagram 563 when indicating "Accident" or when varied to "Census", "Dust cloud", "Fallen tree", "Frost damage", "Overhead cable repairs", "Runners in road", "Smoke" or "Walkers in road",
may be retained only for so long as the hazard indicated by the sign continues to exist or is expected to recur in the near future.
(4) The sign shown in diagram 633, 636.2 (except when varied to show the name of a traffic authority), 829.1, 829.2, 829.3, 829.4, 829.5 or 1063 may be placed on or near a road only by a constable in uniform or a person acting under the instructions or authority of the chief officer of police.
(5) The sign shown in diagram 829.5 may only be placed on or near a road in an area where police speed checks are from time to time carried out.
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