Diagram 557 slippery road sign is positioned on carraigeways with increased chance of vehicles skidding and losing control. Roads that usually have surface water, loose surface that need remedial work.
Material: R2/RA2 reflective overlay on aluminium composite backing
11.3.1. The slippery road sign, diagram 557 (S13‑2‑6, see Figure 11-4), is intended for use where the danger of vehicles skidding is greater than normal. A plate “For” and a distance may be used with this sign. The degree of danger cannot be precisely defined as this depends 60 upon the skid resistance value, speed of traffic and the degree of superelevation on bends. It is for the traffic authority to judge whether overall conditions are sufficiently sub-standard that special warning is necessary. Detailed guidance can be found in HD 28, Skidding Resistance, in Volume 7 of DMRB. Care must be taken not to over‑use the sign, or its credibility will be undermined. Remedial works to improve the skidding resistance of the road surface or to improve drainage should be undertaken as soon as practicable and the signs removed on completion of the works.ne mile.