Page:UK Traffic Signs Manual - Chapter 4 - Warning Signs. 2013.pdf/21

 sited at a distance from the hazard significantly different from that recommended in Appendix A, a distance may be added in accordance with Schedule 16 item 6 (see Appendix C). An indication of the distance over which the restriction extends may be given, e.g. "Single file traffic for 400 yds". If the road indicated is a side road, an arrow may be added, pointing horizontally to the left or to the right. Details are shown on the working drawings (see para 1.8).

If a road is wide enough for only one line of vehicles but there are passing places marked with diagram 822 "PASSING PLACE", diagram 821 "Single track road with passing places" should be used at each end of the single track section. The legend "with passing places" may be varied to "No passing places for" and a distance in yards or miles.

The loss of a lane on a dual carriageway road, on a slip road at a grade separated junction or on a one-way street should be indicated using the sign to diagram 872.1. The sign illustrated is for use on a primary route. The background colour is varied to blue when the sign is used on a motorway and to white with black symbols and border when used on a non-primary route.

The size of diagram 872.1 is determined by the measurement across the arrowhead. A sign is placed on each side of the carriageway, and the pair repeated on roads with higher traffic speeds. Sizes and distances from the start of the taper are detailed in table 42 On motorways and other dual three-lane carriageway roads subject to a 70 mph speed limit, three pairs of signs should normally be provided, at 800, 360 and 180 metres from the start of the taper.

Guidance on the associated road markings where the number of lanes is reduced on a high-speed road can be found in Chapter 5 (para 4.53). 20