Exploring Characteristics and Fundamental Relations of Area-Wide Vessel Traffic Flow

摘要

Vessel traffic flow characteristics and their relations have been crucial research topics for marine traffic analysis and navigation simulation, and is also the basis for through capacity and congestion index calculation. This study aimed to propose a measurement method of area-wide vessel traffic flow characteristics by extending Edie's definitions of traffic flow rate, density, and speed to multi-directional navigable waters using three-dimensional vessel trajectories, and identify an appropriate model to describe their relations. Edie's definition on traffic flow rate, density, and speed are introduced and extended. Then, three-dimensional spatial-temporal vessel trajectories are plotted and a boundary interpolation algorithm is proposed to measure the three area-wide vessel traffic flow characteristics. Two cases are utilized to test the proposed methodology. Results show that (1) extracting and modelling area-wide vessel traffic flow characteristics are feasible; (2) area-wide vessel traffic Fundamental Diagrams present similar patterns with that of road traffic, but change in interval rather than a clear curvilinear relationship; (3) modified Greenberg's logarithmic models are used to determine the upper bound and lower bound of the relation intervals.