Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/94

SIGNING PRINCIPLES The "Single file traffic" plate to diagram 518 is used with a "road narrows" sign to diagram 516 or 517 to warn that traffic previously travelling in more than one lane must proceed in single file; see Chapter 4 for further details. Where there are two lanes of opposing traffic they can be separated by cones, cylinders, reflecting road studs, barriers etc.

The reflectorised "hazard marker" signs, to diagrams 560 and 561 are used on unlit or poorly lit roads to delineate the edge of the carriageway. They may be mounted on suitable posts or stakes, see Chapter 4 and BS EN 12767:2007. On single carriageway roads they must be double sided and show red on the left-hand side of the carriageway and white on the right-hand side. On dual carriageway roads they must be single sided and show red on the left-hand side of the carriageway and amber on the right-hand side. They may also be used to mark individual temporary obstructions close to the running lane, which cannot otherwise be adequately marked by cones and warning lights. This subject is dealt with in more detail in Chapter 4.

"TRAFFIC UNDER SIGNAL CONTROL" sign to diagram 7021. This should be used in combination with a "road works" sign to diagram 7001 at every side road leading to an uncontrolled junction within a length of road controlled by portable traffic signals. This procedure must be used only when traffic held at the signals is visible to the joining traffic.

"STOP AT CENSUS POINT" sign variant to diagram 830. This may be used in connection with a census only when the taking of the census has been approved by the traffic authority for the road, the chief officer of police of the police area in which the road is situated and by or on behalf of the Secretary of State. For more information on surveys, see Section D3.26. 93