Roundness Ratio Requirement of Glass Beads for Reflective Road Markings

Reflective glass beads play a role of retro-reflection in the road marking paint to make road markings reflective.

The reflective performance of road lines is formed that car lights will be reflected back to the driver's eye by glass beads in the marking paint. Each glass beads protrusion of the coating surface is a reflective element, when car lights incident on glass beads, the incident light in the glass beads refracted at its inner and is reflected back in the direction of light source, on the reflection coating layer formed by the bottom of the glass beads and paint coatings.


Good quality glass beads are transparent spheres, glabrous and round and no obvious bubbles and impurities in exterior appearance. What is the most important is the roundness ratio of glass bead.

Is the higher roundness ratio of glass beads, the better for reflective road markings?
The answer is certainly no.

In the road marking industry, a reasonable roundness ratio of reflective glass beads is more than 70 percent. But it is not the higher roundness ratio the better. Because, over-high spherical rate of glass beads will make the reflected light too strong, cause strong visual stimulation to the driver. Thus a small amount of irregular glass beads is required, to produce a diffuse reflection, making the reflected light soft.