Evaluation of pavement marking materials for wet night conditions

Abstract

Traffic pavement markings serve to regulate, to guide, to channelize traffic and to supplement other traffic control devices. Under favorable conditions, traffic markings may provide information to the vehicle driver without diverting his attention from the roadway. However, the visibility of pavement markings may be considerably reduced by wet night driving conditions. This research investigated the visibility of eight pavement marking materials for both wet and dry conditions. Test markings of the materials were placed on three highways and their performance recorded for a period of eighteen months. Field measurements included periodic recording of retroreflectivity and percentage of missing material. The field-tested materials were also subjected to controlled laboratory testing for dry and wet conditions. Subjective evaluations and quantitative evaluations of in-place roadway markings were made in order to determine a minimum marking luminance level for reflective markings. A minimum luminance value was also determined through subjective evaluations and quantitative measurements for controlled and repeatable laboratory conditions. An equation was developed to express the relationship between the field and laboratory luminance subjective evaluations (A).