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OD矩阵是公交线网规划和线网优化的重要依据.OD矩阵反推是获取公交OD数据的有效方法.相关文献中，针对城市整体公交体系的研究较少.依据西宁市建成区所有公交线路上客、下客、车上乘客的调查数据，采用VISUM软件构建了基于等概率下客分布、距离概率下客分布的公交OD矩阵反推模型；然后在VISUM全市整体公交模型中，将各线路反推所得到的OD矩阵归并至交通小区，并通过模型分配得到的路段客流与线路调查得到的路段实际客流比较，检验公交OD反推方法的有效性.研究表明，等概率分布OD矩阵反推在西宁案例中的精度与可靠性较高.最后指出，乘客在各站的下客概率影响因素较多，把握并合理运用其规律是公交OD反推的关键.

Bus OD Matrix Estimation by VISUM Model:Case of Xining of China

The origin destination (OD) matrix is important for transit line planning and optimizing. It also provides an effective way to get the bus OD matrix data. However, the studies on city’s whole transit lines are still very limited. Based on the boarding, alighting and thorough passenger data of every bus line in Xining city, the paper develops a bus OD matrix estimation model with VISUM by the equal alighting probability and probability related to riding distance. In this model, the OD matrix of traffic zone is estimated from each bus line. Then, the reliability of the OD matrix estimation is analyzed by comparison of two kinds of road passenger flow: one is obtained from traffic assignment, and the other comes from traffic survey of bus line. The result indicates that the OD matrix estimation by method of equal alighting probability is accurate and effective. Finally, it draws the conclusion that the alighting probability at bus stop is influenced by many factors, and its mechanism should be analyzed and used reasonably.