收费情形下一类弹性需求混合交通均衡的效率损失

收费是降低交通均衡效率损失的一种重要方法，本文对收费情形下多用户类弹性 需求交通均衡分配的效率损失进行了研究.首先，构建该类交通均衡分配在两类不同出行决策 准则下的变分不等式模型.然后，通过解析推导法分别界定了其在不同出行决策准则下的效率 损失上界，并探讨了它们与网络参数的关系.最后，给出了数值算例.结果表明：两类效率损失 上界都与路段出行时间函数、路段收费向量、出行者的出行时间价值系数、用户均衡时社会总 收益与社会总剩余之比相关；费用度量出行决策准则下的效率损失上界还与系统最优时的社 会总收益与均衡时社会总剩余之比有关.

On Efficiency Loss of a Mixed Traffic Equilibrium with Elastic Demand under Road Pricing

The road pricing is one of the important ways to reduce the efficiency loss of traffic assignment. This paper investigates the efficiency loss of multiclass traffic equilibrium assignment with elastic demand under road pricing. Firstly, this paper formulates two variational inequality models for this kind mixed traffic equilibrium assignment under time- based decision criterion and monetary- based decision criterion, respectively. Then, the upper bounds of efficiency loss caused by this two decision criterion are analytically derived and the relations to some network parameters are discussed. Finally, a numerical example is taken to validate our analytical result. It is shown that the upper bounds of efficiency loss caused by the two kinds decision criterion all depends on the type of link travel time function, road pricing vector, the value of time of users, the ratio of user benefit and the total social surplus under time-based at traffic equilibrium assignment state. The upper bounds of efficiency loss caused by the monetary-based assignment also depends on the ratio of user benefit at system optimum and the total social surplus under monetary-based at traffic equilibrium assignment state.