Highway Glass Beads

Glass Beads

Glass beads are an essential part of traffic safety systems. The beads increase a driver’s ability to be able to see road markings at night and in bad weather conditions due to the retro-reflective properties of a glass bead. The light is refracted in the beads, allowing it to be reflected by the road marking back towards the driver.

Glass beads are used both as drop-on beads on top of road markings and as premix beads in some types of road marking. European regulations regarding performance criteria, test criteria, quality requirement etc. can be found in the standards EN1423 and EN 1424.

Retroreflection

Retroreflection refers to the light reflected back to the driver from the vehicle headlights. The level/intensity of the light reflected back to the driver is a key measure of how effective a road marking is. Retroreflection is measured with an equipment known as a retroreflectometer, which measures and calculates the level of retro-reflected light at a specified geometry. This geometry refers to the distance from the observer to the illuminated point of interest, which is 30 meters away. It measures the retroreflected light from the road marking. This is measured in millicandelas per square meter per lux (mcd/m²/lux).