基于 Select Link 的区域 OD 矩阵更新方法研究

在大范围机动车 OD 调查难以开展的背景下,通常采用路段流量进行 OD 反推,针对传统路段流量反推法无法检验分布结构的缺点,提出一种利用局部路段真实 OD 矩阵进行区域 OD 矩阵更新的方法。即从区域先验 OD 矩阵中减去模型 Select Link 计算的特定路段 OD 矩阵,再加上该路段真实 OD 矩阵,通过替换将区域分布结构更新。当区域多个路段真实 OD 矩阵需要替换到区域 OD矩阵中时,采用两步循环替换法:第一步,单个路段循环替换,每个路段替换后的 OD 矩阵作为下一路段 Select Link 计算的输入;第二步,利用第一步的最终结果,对所有路段 OD 矩阵进行整体替换。以桂林绕城(东)高速为例进行验证,与传统 OD 反推方法相比,结果 OD 矩阵长途出行比例提高了7%,反映了区域机动车分布变化规律,路段流量分配值与调查值相关系数达0.99,证明了更新后 OD 矩阵的准确性。

A Regional OD Matrix Estimation Method Based on Select Link Analysis

It is difficult to carry out a wide range of origin-destination (OD)surveys for vehicles.The regional OD matrix is commonly estimated by traffic flow in road sections.Considering the fact that the distribution structure cannot be verified through traditional OD estimation methods,a new method is proposed.This method updates the regional OD matrices with a Select Link analysis and replaces them with “real”OD matrices.Firstly,a specific sectional OD matrix computed by Select Link is subtracted from the regional priori OD matrix;then a “real”matrix of this road section is used to update the distribution of regional traffic flow.A two-step iterative replacement procedure is applied when there are multiple road sections in the regional priori OD matrix whose OD matrices need to be replaced by the “real”ones.The first step is to replace each sectional OD matrix one by one.One replaced matrix will be used as input for the next link. The second step is to replace the whole regional priori OD matrix based on the first step.A case study of Guilin Ring (East)highway has been conducted to verify this method.Compared with the traditional OD estimation methods,this new method resulted in an increase of 7% of the long-distance travels,which can reflect the variation of regional distribu tion of vehicles .The correlation coefficient between the assigned and the surveyed traffic flow of road sections reaches 0.99,which verifies the accuracy of the updated regional OD matrix.