Hazard signs are used to highlight to approaching traffic a marked change in the direction of travel and the presence and width of an obstruction.
Guide signs are generally rectangular. Hazard signs are rectangular and generally consist of a series of alternate black and white bands. The white portion is always reflectorized, but the reflective material may cover only the central portion of each white band to achieve a balance between the areas of black and white under headlight illumination. The bands may consist of either diagonal strips where only a target is required, or of chevrons where directional, as well as target, properties are desirable.
Typically, there are 4 types of hazard marker:
- Uni-directional Hazard Marker – used to guide approaching traffic to the direction indicated by the chevrons i.e. to the left or right as required.
- Bi-directional Hazard Marker – used to delineate the nose of an island or other obstruction where traffic may pass the obstruction on either side.
- Width Marker – normally erected in pairs, one on either side of a vertical obstruction facing in the direction of traffic flow.
- Obstruction Marker – used to delineate obstructions such as road closures or obstructions above the road.