Thermochromic road markings for real-time ice and snow alerts

Climatic conditions are critical factors in road accidents. Under adverse scenarios, such as the presence of ice or snow on the pavement, surface friction is significantly reduced, compromising road safety. To help alert drivers to these hazards, this study proposes the development of road markings (RM) with thermochromic materials (TM) to act as visual sensors, capable of reversibly changing color when a specific transition temperature (TT) is reached. To achieve this end, a water-based white acrylic paint for RM was functionalized with different rates of TM with TT of 0 °C. After functionalization, the paint specimens' morphological and elemental composition analyses were conducted. In addition, the TM underwent thermal characterization to assess its thermal stability and phase transition behavior. Subsequently, the RM made from these paints were applied to AC10 specimens as prototypes and evaluated for color change using the CIELAB system within a temperature range of −15 to 25 °C. In addition, measurements of the diffuse luminance coefficient (Qd) and coefficient of retroreflected luminance (RL) were performed within the same temperature range. The results confirmed that the RM shift to a pinkish hue at temperatures below 0 °C, with color differences (ΔE) reaching up to 43, while reversibility was demonstrated by the recovery of the original white color and colorimetric parameters upon reheating to positive temperatures. The results also showed that RL and Qd values slightly decreased when the RM were in their colored state but returned to their initial values once the RM were reheated to positive temperatures. Thus, these smart materials exhibit potential for mitigating accidents in regions with harsh winters, contributing to driver safety. • Thermochromic road markings (TRM) developed for ice and snow hazard alerts • TRM change color reversibly from white to pink below 0 °C as visual warning. • TRM maintain optical performance after thermal cycling. • Thermal, chemical, optical and morphological analyses confirmed functionalization. • Promising smart capability to enhance road safety