Influence of Drop-on Application Method on the Retroreflection and Skid Resistance of Road Markings

Abstract

Achieving retroreflection and skid resistance in road marking can pose a challenge. This study collected specifications from twenty-four countries/regions on road markings’ retroreflectivity and skid resistance. In most cases, regulations pertaining to nighttime retroreflectivity specify a minimum skid resistance of 45 pendulum test value. However, not many research studies address the enhancement of retroreflectivity and skid resistance simultaneously. This study presents material optimization and drop-on application methods through repeatability experiments conducted in low-traffic environments, first in first and second field experiments, and later in a third experiment applied on urban roads with continuous monitoring for 12 months to validate their effectiveness. Furthermore, this study examined whether individually distributing glass beads and anti-skid aggregates could improve performance using a dual-box application device. Recommendations are made for different application methods for various road conditions based on the needs of road users. It is suggested that a front box with glass beads and a rear box with anti-skid materials be used for urban roads with adequate nighttime lighting and high road-user density to provide better skid resistance while maintaining good retroreflectivity. In country areas or places with insufficient lighting along roads, uniformly blending the two materials enhances retroreflectivity while still satisfying skid-resistance standards.