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客运和货运用户的边际时间效用通常具有较大差异,这造成了用户在出行时间选择行为上的区别,并对城市公路运输通道的拥挤特性产生影响。既有动态拥挤模型忽略了用户边际效用随时间变化,且变化速度不同这一事实。针对这一问题,通过对时间效用函数进行参数化,将用户异质性引入了时变边际效用瓶颈模型,解决了既有模型无法准确描述客货混合条件下拥挤特性的问题。在获取拥挤特性的基础上,以社会福利最大化为目标确定了针对客货混合用户的最优定价策略,并讨论了该策略对各类用户产生的福利效应。结果表明,在目的地边际效用增长率较高的用户会更早到达,且这一拥挤特性在无收费用户均衡以及社会最优收费的状态下均存在。社会最优收费由用户在出发地和目的地的边际时间效用决定,该定价策略可使拥挤收费计入货运用户的边际成本,从而使货运用户更容易接受拥挤收费政策。当社会最优收费完全不返给用户时,全体用户的间接效用与无收费均衡状态保持一致,但拥挤排队现象可以被完全消除。如果将收费均等地返还给全体用户,社会最优收费可以实现帕累托改进。如果将收费更多地返还给在目的地边际效用较高的用户,可以促进用户生产效率的提高。
The marginal-time utility of passenger and freight transport users often has large differences, which leads to the difference of user’s choice of travel time and affects the crowding characteristics of urban road transport corridors. The existing dynamic congestion model ignores the fact that the marginal utility of users changes with time and the rate of change is different. To solve this problem, the parameterization of time utility function is used to introduce user heterogeneity into the bottleneck model of time-varying marginal utility, which solves the problem that the existing model can not accurately describe the congestion characteristics under the condition of mixed passenger and cargo. On the basis of obtaining the congestion characteristics, the optimal pricing strategy for mixed passenger and cargo customers is determined with the goal of maximizing social welfare. The welfare effect of the strategy on all kinds of users is also discussed. The results show that users with higher marginal utility growth rate at destination will arrive earlier, and this congestion feature exists in the state of no-charge user balance and social optimal charge. The optimal social charge is determined by the user’s marginal utility at the place of departure and destination. This pricing strategy allows for congestion charges to be included in the marginal cost of the shipping user, making it easier for the shipping user to accept the congestion charging policy. When the optimal social charges do not return to the user at all, the indirect utility of all users is consistent with the state of no-charge balance, but crowding-queuing can be completely eliminated. If the fees are returned equally to all users, the optimal social charge can achieve Pareto improvement. If more fees are returned to users with higher marginal utility at destination, user productivity can be boosted.