Prediction of Road Marking Performance

From the road user’s point of view the night-time visibility of road markings during wet conditions is of great importance, and instruments aimed for mobile measurement of the retroreflectivity of road markings are available. However, due to splash from the tires of the measuring vehicle, it is almost impossible to carry out measurements on wet road markings. The purpose of this study was to investigate if results obtained on dry road markings can be used for prediction of the retroreflectivity of wet markings. Furthermore, the possibility of predicting skid resistance of wet road markings from results obtained on dry road markings was examined. Physical measurements of a number of performance parameters of road markings showed that the retroreflectivity of a dry road marking surface and mean profile depth (texture) of the surface in question can be used both for prediction of retroreflectivity and skid resistance of wet road markings. As retroreflectivity and texture can be measured using mobile equipment, wet performance parameters can be estimated from measurements carried out on dry markings at speed. The precision of the models was found to be acceptable, which means that they seem to be useful for classifying performance of road markings. Based on the models, performance classes for retroreflectivity and skid resistance of wet road markings are proposed.