THE FUNCTION OF ROAD MARKINGS DURING WET CONDITIONS

Road markings are used to enchance the visual guidance of the road at night, and are normally plane with the road surface. When driving in heavy rain and darkness, almost all the light from the vehicle will be reflected away from the driver and the road markings become practically invisible. Profiled road markings can break a specular water surface so that they are more visible in dark and wet conditions. A number of profiled lines have served as edge markings on part of highway 23 in Sweden and have been compared with a plane reference line. The results show that all except two of the profiled lines meet the standard for retroreflection during wet conditions specified in the Road Design Manual of the Swedish Road Administration. The subjective evaluations of relative visibility that were carried out show that the profiled lines are more visible during wet and dark conditions than the plane reference line. (A)