A Study on Waterway Freight Impedance and Distribution Models on Yangtze River Based on Data of Ship AIS and Visa

This study aims to figure out dynamic and complex impacts of various sections of Yangtze River on waterway freight transportation.Based on AIS and residence time of ships at the Three-Gorges Dam, a freight impedance model considering ship course, waterway segment and time is developed.Meanwhile, a time impedance matrix among important ports of the Yangtze River in different months is obtained using Matlab.Taking data of ship visa in October 2010 as a case study, the parameters of two types of gravity distribution models based on distance impedance matrix and time impedance matrix are calibrate respectively.Then corresponding models of distribution of freight transportation are established.With these models, the distribution in October 2012 is predicted.A Trip Length Distribution (TLD) method is applied to check the four predicted distributions with the actual distribution in October 2012.The results show that the Coincidence Ratios (CR) values got from the inverse power function and the exponential function based on the time impedance are 0.83 and 0.86 respectively;which based on the distance impedance are 0.81 and 0.82 respectively.This study indicates that the gravity distribution model based on time impedance has a better predication performance of inland freight transportation of the Yangtze River.