In addition to the functional requirement of a road, there are safety and decorative aspects to be considered.
Warning and stopping areas, such as pedestrian crossings, roundabouts, bus stops and parking, require an additional component to improve friction and anti-slip properties.
There is also a need in contemporary road construction to increase the visibility of particular features - cycle lanes, bus stops, multi-directional junctions, etc. This can be achieved by either applying a pigmented coating to the aggregate or by colouring the asphalt.
The process of mixing colour pigment with black bitumen is very difficult; the consistent application of conventional powder pigments is challenging given the need to accommodate all weather conditions.