居民出行分布预测是城市交通需求分析中的一个重要环节,对城市交通需求分析起着承前启后的作用.预测模型中交通阻抗函数的选择和相关系数的标定是重点和难点,关系着整个模型的收敛性与精确性.通过对常用的出行分布模型以及交通阻抗函数的特点和适用条件比较和分析,明确预测模型和交通阻抗函数的选择依据.选择双约束重力模型作为预测模型,选取符合大中城市交通现状的指数型函数作为交通阻抗函数,并提出运用迭代标定算法对模型中相关系数进行标定,给出了算法关键步骤.结合西安市碑林区内交通情况对试模型和算法进行测试.结果显示模型具有很好的适应性和收敛性,算法具有较高的效率和精确度.%The forecast of inhabitant trip distribution is an important part, and play a connecting role, in analysis of city traffic demand.Selecting traffic impedance function and the relative coefficient calibration which affect the convergence and exactitude of the whole model are significant and difficult. Discusses several frequently-used trip distribution models and traffic impedance functions, compares their characteristics and applicable conditions, and determines the basis for selection of forecast model and traffic impedance function. Then selects double-restriction gravity model as the forecast model, and the index function which is suitable to medium-sized cities as the traffic impedance function, and brings forward iterative calibration algorithm to determine the relative coefficient, displays key steps of the algorithm. In the end the model and the algorithm is tested by applying to Beilin District in Xi'an city, the results show that the model has the ability of better adaptation and convergence, and the algorithm has the advantage of more efficient and exactitude.
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