Effects of Ultraviolet Irradiance and Temperature on the Yellowing Behavior of White Pavement Markings

Pavement markings are critical traffic safety facilities that provide continuous and clear visual guidance to road users, thereby supporting traffic order and driving safety. During long-term service, however, white pavement markings are prone to yellowing under ultraviolet (UV) irradiance and elevated temperatures, which may reduce visibility. This study conducted accelerated aging tests on white thermoplastic and two-component pavement markings under four levels of ultraviolet irradiance (0–1.5 W/m2 at 340 nm) and temperature (20–80 °C) to quantitatively characterize the macroscopic evolution of yellowing (YI) under controlled environmental conditions. Generalized linear mixed-effects models (GLMMs) were then used to quantify the effects of UV exposure, temperature, and time on the yellowing behavior of white pavement markings. The results indicate that temperature is a key environmental driver of YI increases. UV irradiance also has a pronounced promoting effect, and the yellowing responses differ markedly between material types. The results clarify how UV irradiance, thermal conditions, and material systems jointly influence the yellowing behavior of white pavement markings, providing a scientific basis for evaluating anti-yellowing performance, improving durability design, and guiding engineering applications under complex environmental conditions.