Effects of Ultraviolet Radiation and Temperature on the Daytime Optical and Colorimetric Properties of Pavement Markings

Pavement markings are important components of roadway infrastructure, delineating lane boundaries and providing guidance for traffic. However, long-term exposure to the natural environment leads to progressive deterioration of their visibility. This study investigated the degradation patterns of four optical and colorimetric indicators related to the daytime visual performance of pavement markings: luminance factor ( β ), yellowness index (YI), yellow axis ( b ), and color difference (Δ E ). Accelerated-aging tests were conducted using a Q-SUN Xe-3 xenon arc chamber under different combinations of ultraviolet (UV) irradiance and temperature. The performance changes of white and yellow thermoplastic and two-component pavement markings were examined under varying temperature levels (20°C, 40°C, 60°C, and 80°C) and UV irradiance intensities (0 W/m 2 , 0.51 W/m 2 , 1.01 W/m 2 , and 1.50 W/m 2 ). Based on the experimental results, separate multiple linear regression models were developed for white and yellow markings. Results indicate that the measured daytime optical and colorimetric properties are affected by temperature and UV irradiation. As temperature and UV irradiance increase, the magnitude and rate of changes in the measured indicators increase significantly. Within the tested product set, the methyl methacrylate based two-component formulations exhibited smaller changes in the measured optical and colorimetric indicators than the thermoplastic formulations, while the white formulations generally exhibited smaller colorimetric changes than the yellow formulations. These findings provide an experimental basis for material weathering assessment and daytime optical and colorimetric deterioration evaluation under varying environmental conditions, offering valuable insights for pavement-marking material evaluation and optimization.