多种Logit路径选择模型对多层次交通网络的性能影响

Impacts of Logit Route Choice Models on Performance of Hierarchical Traffic Network

研究了多种Logit路径选择模型应用于多层次交通网络时对网络性能的影响。依据网络层次特征定义了广义路径费用;选取4种典型的Logit模型——单层的多项式Logit(MNL),C-Logit(CL),Path-Size Logit(PSL)以及双层的交叉巢式Logit(CNL)模型,对它们分别构建了适用于多层次网络的等价数学规划模型(MP);对不同层次结构和分散参数取值,利用VC++编程求解4个等价数学规划模型,并计算了系统最优的流量分配。分析表明:3种OD需求下的所有Logit模型所得网络总行程时间费用(NTTC)都高于通过系统最优分配得到的NTTC;利用考虑重叠的CL、PSL、CNL模型所得NTTC皆大于不考虑重叠的MNL模型,且构造越复杂的Logit模型所得NTTC越高;对各个Logit模型而言,层次性交通网络的NTTC要小于没有层次性的情况且层次越高时NTTC越小。

The impact of a variety of Logit route choice models on network performance when they are applied to hierarchical transportation network is studied. The generalized path cost is defined based on network hierarchical feature. Four Logit models, i. e. , the models of single-level muhinomial Logit （MNL） , C-Logit （CL）, Path-Size Logit （PSL）, and bi- level cross nested Logit （CNL）, are selected. The equivalent mathematical programming （MP） models of the 4 Logit models for hierarchical network are established respectively, which are solved with VC ＋ ＋ in the cases of different hierarchical levels and different dispersion parameter values, and the flow patterns of system optima （SO） are also calculated. The analysis shows that （ 1 ） for three kinds of OD demand, the total network travel time costs （NTTCs） resulted from all of these Logit models are higher than that obtained by the system optimal assignment method; （2） CL, PSL and CNL models that consider overlapping routes produce greater NTTCs than MNL model that does not consider overlapping, and the Logit model with more complex structure results in higher NTTC ; （3） for each Logit model, NTFCs of hierarchical transport networks are less than the case without hierarchy, and the higher the hierarchical level, the smaller the value of NTTC.