Characterization of luminescent road markings

Photoluminescent paints for road marking application have been evaluated through laboratory measurements and visibility computations. The luminance decay in the dark was measured after constant excitation during at least 6 hours. To study the effect of night-time lighting conditions, luminance was measured under a constant low illumination (simulating moon and light pollution), and a periodic lighting, simulating automotive traffic. Measurements were also carried out on luminescent road marking applied on real pavement in a full-scale mock-up. Then, possible uses and limits of photoluminescent road markings were investigated through visibility computations based on the COST 331 model. Findings suggest luminescent road markings could strengthen the visual guidance of drivers on the road with traffic by increasing the visibility distance beyond the headlamp beams during the first few hours of the night, and in unlit areas such as bicycle paths, but the performance depends on the night-time illumination level.