Wet night visibility of pavement markings - Dynamic experiment

Fifty-three participants evaluated the visibility of four different pavement marking materials under a simulated rain system operating at 0.8 in. (20 mm) of rain per hour at night while driving a vehicle on a closed test track. The conditions tested include a variable lighting condition, glare, pavement types, and two different vehicle types. The evaluation consisted of determining the detection distance of a start or an end point of a white 4-in. edge line. Results showed that lighting improved visibility and mitigated the effects of glare. Results also showed that the wet retroreflective tape provided the longest visibility distance, followed by equivalent performance of profile thermoplastic; large glass beads with standard paint provided the shortest visibility distance. The detection distance was compared with the retroreflective performance of the pavement marking technology. It was found that a log-linear relationship exists between the retroreflectivity and the detection distance. It was also found that the level of retroreflectivity provided by the materials tested did not provide adequate visibility distance for a sedan with a 2-s visibility time at speeds greater than 45 mph.