Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/31

DESIGN CRITERIA The police can only enforce speed limits where the speed limit signs are correctly placed and conform to the requirements of the Regulations. The extent of any temporary mandatory speed limit should be checked against the temporary order to ensure the limits of the restriction do not exceed those permitted by the order.

Temporary speed limit signs at road works on high-speed roads and other roads should comply with Table 3.4 above. The initial speed limit signing must be placed on both sides of the carriageway, for both dual and single carriageway roads. If the termination signing includes signs to diagram 670 or 671, then it must also be placed on both sides of the carriageway, for both dual and single carriageway roads. The use of the sign to diagram 7290 is no longer recommended.

Where side roads join the road works, and are subject to a different speed limit from that imposed through the works, temporary speed limit signs must be provided for traffic entering the works site. Any existing speed limit signs for traffic leaving the side road must be fully covered with opaque material or removed. Where the limit through the works is:


 * lower than the limit on the side road, a temporary speed limit sign must be placed on each side of the carriageway of the side road, not more than 20 m from the junction and plainly visible to traffic about to enter the works;


 * higher than the limit on the side road, temporary speed limit signs need not be provided on each side of the carriageway of the side road for traffic entering the works, provided that there is a repeater sign in the works not more than 100 m from the junction for traffic travelling in each direction. If the repeaters are more than 100 m from the junction, a terminal sign showing the temporary limit must be placed on each side of the carriageway of the side road, not more than 20 m from the junction.

Similar principles apply at signalled and unsignalled junctions, at crossroads and at all roundabouts.

If the permanent speed limit on the side road is the same as the permanent limit on the road on which works are being carried out, there will be no existing speed limit signs at the junction. In order to indicate to traffic turning off the road with the temporary limit the end of that limit, a sign to diagram 7001 in combination with an "End" plate to diagram 645 or a speed limit sign to diagram 670 indicating the limit in force on the side road must be placed on the near side of the side road not more than 20 m from the junction. If the limit is the national limit, a sign to diagram 671 must be used instead of diagram 670.

All terminal signs must be directly lit (not merely reflectorised) throughout the hours of darkness if they are placed on a trunk or principal road within 50 m of a street lamp. All signs, including repeaters, not required to be directly lit must be reflectorised.

If during the course of the works, any existing speed limit signs require covering, they must be fully covered with opaque material or otherwise removed. It is inadequate and unacceptable to spray masking paint over the numerals on speed limit signs, if this method is used, the entire sign face including the red border must be completely obscured in order to prevent the numerals being visible in daylight or in silhouette against the retroreflective background at night. 30