Nighttime Visibility of Prototype Work Zone Markings under Dry, Wet-Recovery, and Rain Conditions

This paper presents the findings of a dynamic pavement marking visibility study conducted as part of the FHWA Highways for LIFE Technology Partnerships Program Temporary Wet-Weather Pavement Markings for Work Zones project. Three prototype optics-on-paint marking systems employing high refractive index dual-optics drop-on elements were evaluated at night under dry, wet-recovery (immediately after rainfall), and rain conditions. These three prototypes were chosen based on their durability from an initial pool of 22 experimental systems evaluated in a test deck. This dual-optic system was designed to provide good visibility in both dry and wet weather conditions. Two commercially available marking systems were also evaluated as industry benchmarks (one glass beads-on-paint system, one wet-reflective removable tape). Thirty participants driving through simulated work zones on a closed course viewed all of the marking types at night under all three weather conditions. Each driver's task was to identify the direction of work zone lane shift tapers delineated by the markings. In wet recovery, all three prototype marking systems and the wet-reflective tape sustained 60% to 80% of their dry average detection distances, and in rain, they sustained 50% to 70% of their dry average detection distances. In contrast, the average wet-recovery and rain detection distances for the conventional glass beads-on-paint benchmark system dropped to 28% and 17% of the dry detection distance, respectively. In addition, participants failed to detect the conventional glass beads-on-paint benchmark system in nearly half of the observations in the rain condition.