基于K短路的多路径交通分配研究

Multi-path Traffic Assignment Based on K Shortest Paths

基于K短路,通过使用Logit配流模型研究道路交通网络在多路径流量分配时的性质。首先,研究了Logit模型中参数θ与配流结果之间的关系,从路网平均阻抗与路段阻抗方差最小的角度出发,选择合适的θ值对路网流量进行分配;之后,使用Yen算法求解K短路问题以构建可选路径集合;最后,结合算例对K短路在多路径流量分配时的性质进行了研究。实例研究表明,随着参数θ值的增加,路网平均阻抗与路段阻抗方差先减小后增加,当θ？=1时路段阻抗方差最小;随着K值的减小,路网平均阻抗与路段阻抗方差持续增加,当K=5时路网平均阻抗和路段阻抗方差都在可接受范围之内且计算量最小。本文加深了对于K短路的认识,有利于K短路在实际运用中的推广。

On the basis of K shortest path, this paper analyzes the feature of road traffic assignment with the Logit distribution model. Firstly, this paper verifies the relationship between the value of θ in Logit model and the results of the assignment, and chooses a suitable value of θ for the traffic assignment from the sides of network average impedance and link impedance variance; Then, this paper uses the Yen algorithm to solve the K shortest path problem and build an optional path set; Finally, this paper analyzes the property of K shortest path on the multi-path traffic assignment with a case study. The results indicate that the network average impedance and the link impedance variance are decrease first and then increase with the increase of the θ, when θ = 1, the link impedance variance is the smallest; the average impedance and the link impedance variance are increasing continuously with the K values decreases, when K=5, the average impedance and the impedance variance is acceptable and the calculated quantity is the smallest. This article deepens the study of K shortest path and is contributes to the application of K shortest path in practical application.