Preparation and performance of a novel perceptual road marking based on flexible piezoelectric thin film sensor

This study addresses the issues of complex installation and difficult maintenance associated with traditional piezoelectric devices in road applications. We propose an innovative approach by embedding flexible PVDF film sensors into a two-component traffic marking system, enabling conventional markings to function as traffic detection devices, called intelligent road marking systems, for smart transportation. The influence of key parameters such as roller pressure, frequency, and thickness of the upper marking layer on the electrical output of perceptual markings was studied using indoor and outdoor experiments and finite element simulations. The design and durability performance of perceptual markings were evaluated. The results indicate that the peak voltage output of the sensor varies with load changes. Furthermore, a thicker upper marking layer significantly reduces sensor sensitivity. Finite element analysis shows that embedding the flexible sensor within the marking has minimal impact on the internal structure, offering an advantage over direct embedding in the road surface. The study also examines the effect of two common encapsulation materials on durability. It was found that PET encapsulation material withstood more stress and exhibited fewer strain-sensitive areas compared to PI, making it more suitable for long-term use in road environments. Finally, the perceptual markings demonstrate good durability and stability after 300 simulated wheel-loading cycles and 200,000 periodic loading tests.