As the striping material wears, the glass spheres that are blended in the material are exposed to give
continuous retro-reflectivity, increasing the life of the material.
In thickly-applied materials, such as thermoplastic or MMA, the blended spheres are referred to as
"intermix" beads. The size of the intermix beads in these materials is usually similar to the size of the
drop-on highway safety marking spheres.
In thin film paint materials, the blended spheres are referred to as "premix" beads. Premix beads are
typically smaller than drop-on paint highway safety marking spheres.
Both intermix and premix give continuous retro-reflectivity on pavement markings that wear and
lose the reflective top dressing of highway safety marking spheres.