Micro-Energy Harvesting and Self-Powered Sensing for Intelligent Road: A Comprehensive Review

The sustained growth in global road mileage, combined with rising public expectations for improved travel safety and comfort, has created an urgent demand for sensing technologies in road systems. Nevertheless, conventional monitoring methods are increasingly insufficient for modern intelligent roads (IRs), which represent next-generation infrastructure requiring efficient and sustainable sensing solutions. Existing sensor systems that rely on traditional power sources or cabled power supply suffer from inherent limitations, including short operational lifespans and high maintenance costs. At the same time, current road micro-energy harvesting technologies struggle to meet the demands of large-scale distributed sensor networks in IR, underscoring the critical need for self-powered sensing solutions designed for IR. This review identifies the power supply bottleneck inherent in distributed sensor networks of IR, provides a critical comparison of potential solutions with a focus on micro-energy harvesting technologies, and offers a comprehensive review of the practical applications of self-powered sensors (mainly piezoelectric nanogenerators and triboelectric nanogenerators) within road systems. Furthermore, it proposes forward-looking recommendations and developmental prospects for the field, thereby offering theoretical support to advance the large-scale implementation of self-powered sensing in IR systems.