Page:UK Traffic Signs Manual - Chapter 4 - Warning Signs. 2013.pdf/30



The sign to diagram 528 should be used where a hump bridge is so severe that unless drivers are forewarned they might lose control of their vehicles. If visibility is inadequate, double white lines or a hazard line should be laid in accordance with the normal criteria (see Chapter 5). If the hump bridge hides a further hazard, another sign indicating this should be provided on the same post (with the sign indicating the first hazard encountered placed uppermost). If there is a risk of long vehicles grounding on the bridge, diagram 782 (see para 21.13) should be used also, mounted below diagram 528. They should be sited, with a distance plate, on the approach to a junction at which vehicles can divert, and repeated at the standard siting distance from the structure (see Appendix A).

Signs to diagram 528.1 should be used where a bridge parapet, abutment or other obstruction is immediately adjacent to, or encroaches onto, the carriageway. This includes any parapet or abutment on the off side where it would be a hazard to drivers overtaking or passing a temporary obstruction on the near side. In addition to the risk to passing road traffic, damage to a parapet can also result in considerable danger to rail traffic. It is therefore particularly important that signs to diagram 528.1 on parapets or abutments of bridges are correctly installed and maintained to a high standard. The use of these signs helps to make the vulnerable parts of a structure more conspicuous. If the obstruction is accompanied by a narrowing of the carriageway, "road narrows" signs to diagram 516 or 517 (see section 4) and edge lines should also be used. The signs should be used as in the diagram, sloping downwards towards the carriageway. The Regulations permit the use of yellow material which is both retroreflective and fluorescent (see para 7.6).

The sign to diagram 529 should be used in advance of opening bridges (lifting or swing). If movement onto a bridge is controlled by wig-wag signals to diagram 3014, a plate to diagram 773 (see section 21) should be added. 29