What parameter determines the retroreflectivity performance of drop-on glass beads in wet traffic paint lines?

1. The chemical viscosity of the liquid asphalt emulsion sealer binder rating.
2. The color tint shade of the underlying oil-spot primer coating.
3. Proper bead embedment depth, ideally 50% to 60% of bead diameter in paint.
4. The diameter thickness of the aluminum spray gun tip nozzle orifice.