Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/30

 of speed restriction. The Regulations require signs to diagram 7001 with an "End" plate to diagram 645 to indicate the end of a temporary mandatory speed limit although a combined end of works and the permanent speed limit sign may be used, see Section 4.14.

The designer should consider where to site the signs to ensure clear visibility (see Section D4.4). The resulting location of the signs may alter the distance from the works given above, but must be accurately referred to in the traffic regulation order.

In general, a temporary speed limit should not be introduced where the length of restriction would be less than 800 m on dual carriageway roads and 400 m on single carriageway roads, measured between the initial speed limit sign and the sign indicating the end of all restrictions.

At sites where the length of road affected is 800 m or longer, repeater signs at regular intervals along the length of the works are required to remind drivers of the maximum speed and ensure better compliance. See Table 3.4, NOTES for details of the spacing of these repeater signs.

NOTES: 29
 * 1) The recommended maximum spacing of repeater signs for temporary speed limits is as follows:
 * 2) *for temporary speed limits of 50 mph or more: consecutive repeater signs on the same side of the carriageway not more than 700 m apart, with a maximum of 450 m between consecutive signs on alternate sides of the carriageway,
 * 3) *for temporary speed limits of 40 mph: consecutive repeater signs on the same side of the carriageway not more than 500 m apart, with a maximum of 350 m between consecutive signs on alternate sides of the carriageway;and
 * 4) *for temporary speed limits of 30 mph or less: consecutive repeater signs on the same side of the carriageway not more than 400 m apart, with a maximum of 250 m between consecutive signs on alternate sides of the carriageway. On lit roads subject to a temporary limit of 30 mph, repeater signs must not be used.
 * 5) Further advice on spacing and size of signs for use on non-trunk roads, including side roads, can be found in Chapter 3.
 * 6) The size of signs on a side road should be one size larger than that recommended in Chapter 3 for the permanent signs.
 * 7) Except where required for signing of enforcement cameras, see paragraph D4.15.10, or where required to avoid sign obscuration, the spacing between repeater signs on the same side of the carriageway should not normally be reduced from that specified in Note 1. Placing repeater signs in pairs on both sides of the carriageway is discouraged due to the increased exposure to workers in maintaining this arrangement.
 * 8) If the police or other enforcement body request additional signs or reduced repeater spacing, the designer should confirm with the body that a risk assessment has been carried out of the effect of the requested signs on road worker safety.