Durability of waterborne road marking systems with various glass beads
Horizontal road markings belong to ubiquitous safety features on all roads. Based on scientific evidence, markings with higher retroreflectivity lead to a meaningful drop in the number of accidents. Hence, the recently proposed by the European Road Federation 150×150 formula to maintain lines 150 mm wide and with retroreflectivity at all times above 150 mcd/m²/lx (35 mcd/m²/lx under wet conditions) on every European highway ought to increase road safety. To propose the optimum waterborne road marking system for the 150×150 formula, durability of systems consisting of three types of paints reflectorised with three types of glass beads was assessed. After ±1.4 million vehicle passes (the period included winter road maintenance), drop in retroreflectivity was measured in all systems. The drop was highest in case of a quick-dry paint and lowest with high-performance paint. In all of the cases, selection of glass beads also played critical role and markings reflectorised with high-performance glass beads showed highest retroreflectivity under dry and wet conditions both initially and after the test – such system should be the first choice to maintain the 150×150 formula. The systems where other glass beads types were utilised performed satisfactorily or very good. Since failures after one year were measured with only a few systems, the testing continues with hopes to furnish a two-year paint-based road marking system.