Forecasting the performance of luminescent road markings from laboratory measurements: Towards standardization

The application of luminescent road markings is becoming more and more widespread to enhance the visibility of road markings and improve visual guidance in unlit areas. However, luminescent road markings are more or less visible during the night depending on the light emission due to photoluminescence. Current standards on road marking are not suitable for such innovation, and new methodologies, considering the variable visual performance of luminescent road markings, are required towards regulations. In this context, the present paper proposes a model which predicts the cumulative time during which a luminescent road marking is brighter than a traditional one taken as reference. It uses as input the luminance decay curve in the dark of the luminescent markings obtained in standard and reproducible conditions in laboratory, its reflection properties and the nighttime illumination. The model was validated using a dataset of 18-month recordings in outdoor conditions. It performs well ( R 2 = 0.83) even if it underestimates the performance in some favourable conditions. These results are promising in view of future recommendations to ensure the suitability of luminescent road markings at a given location knowing the year-long distribution of the average horizontal illuminance during the night.