Until the mid 1980s, there was only one simple type of road marking in which the various materials (colour, hot or cold plastic etc.) were sprinkled with a mixture of small glass beads and antiskid aggregates (type I). The problem of type I marking: in the case of moisture or rain, a water film forms on the marking surface and extremely reduces the retroflection. This disadvantage has led to the industry pressing ahead with the development of systems with improved night visibility in the case of wet conditions.Correspondingly, a basic idea connects all standard type II markings: parts of the markings are formed so that they protrude from the flat surface of the marking - and thus also from the water film! The reflection on the surface which cannot be prevented in the case of the type 1 marking in wet conditions is thus at least partially avoided and visibility crucially improved even in rainy conditions.
The type II systems can be presently subdivided as follo:
Float coat systems with large aggregates
In the case of float coat systems with large aggregates, night visibility is achieved through the use of large reflex pearls which protrude from the water film in wet conditions. For thick-layer systems, the reflex pearls are either contained in the marking material or a coarse aggregate is used. Agglomerate markings have key advantages compared to smooth markings: lower risk of slipping, no hydroplaning. In the case of an agglomerate marking, parts of the marking are formed in such a way that they protrude from the water film in the event of rain.
Profile markings are particularly well-suited as transverse division lines in tunnels or on roads with alternating 2+1 traffic. The profile marking consists of a 2-3 mm base coat and a 6-7 mm high profile at regular intervals. The driver is warned by the noise development upon driving over this marking, which is caused by the profile.