Coloured surfacing is principally used for demarcation on highways and wherever there is a potential safety issue with vehicles, cyclists and pedestrians. On its own, or in combination with road markings, coloured surfacing emphasises the message of the prescribed markings, increasing driver awareness and encourages caution, thereby improving road safety. Coloured surfaces are not considered as signs or road markings and therefore have no legal status. They are intended to supplement the prescribed signs and road markings.
Surface dressings are generally the most commonly used method as it can be applied to existing surfaces, the colour is achieved by either a coloured aggregate, natural aggregate or a pigmented binder. The selection of material for coloured surfacing will depend on the wear it is expected to receive, the purpose for which it is intended and its skid-resistant requirements. Coloured surface dressings are hand applied for reduced costs and ease of application
Coloured surfacing is available in a variety of different colours, though there is no official scheme for colour usage, some of the more commonly used colours have come to mean certain things. Red is generally used in situations to discourage vehicles encroaching on particular areas of the road, combined with other road markings such as hatching, this gives greater attention to high-risk areas where overtaking accidents are a particular problem. Green, is another popular colour, highlighting areas of the road that are used by cyclists only. Light colour surfacing is a ‘natural’ or buff colour that is a by-product of the natural aggregate used. Its primary use is as a high friction surface to reduce the risk of skidding on bends, junction or pedestrian crossings, however, in these locations, it can also highlight a change in the road layout.