AIS-Driven analysis of nearshore waterway utilization in China

Traditional AIS waterway studies adopt single traffic indicators and overlook transverse channel disparities, overlapping navigation zones, and vessel functional differentiation. To address this gap, this paper constructs a multi-dimensional framework for waterway spatial utilization evaluation based on sailing hours, vessel dimensions, voyage frequencies and shipping functions, focusing on China's nearshore channels in 2023. Combined with multi-index density mapping and raster-based gate-line analysis, we quantify channel utilization across typical coastal waters of Shandong, Shanghai, Zhejiang and Guangdong. Significant regional disparities are observed, with peak annual utilization hitting 86,995 sailing hours per square nautical mile. Overloaded spaces mainly lie in inner trunk routes and overlapping intersections, whereas outer lanes remain underutilized. This transferable framework provides refined governance references for global coastal waters, with targeted strategies proposed to improve navigation efficiency and sustainable shipping operations.