Congestion Pricing Under Multimodal Traffic Considering Equity Effects

With the acceleration of China’s urbanization process,the number of motor vehicles increased sharply,the construction of urban traffic infrastructure far behind the rapid growth of urban traffic demand,followed by serious traffic congestion problem.Traffic congestion pricing is one of the effective ways to solve the problem of urban traffic.Many foreign cities have implemented congestion pricing policies and achieved some results,such as London and Singapore.Many cities in China have also studied and explored the congestion pricing policy,but they failed to implement it due to the lack of public support.Among them,the perceived unfairness after the implementation of the policy is one of the main reasons for the public’s opposition to the congestion charging policy.Therefore,this paper intends to study the pricing problem of urban road congestion pricing from the perspective of fairness of congestion pricing policy,which has important theoretical and practical significance.Firstly,this paper studies and analyzes the equity of the congestion pricing policy,including the analysis of the reasons for the traditional congestion pricing strategy leading to unfairness,the definition,dimensions and influencing factors of the equity of the congestion pricing policy.Secondly,on the basis of studying some commonly used indicators to measure the equity in the field of transportation,this paper chooses the Gini coefficient as the index to measure the equity.Then,a bilevel programming pricing model of congestion pricing considering equity under multi-mode traffic conditions is established.The lower layer,P1,is the optimal transportation network equilibrium allocation model,which comprehensively considers the generalized travel cost function,elastic demand calculation,travel mode choice and travel route choice.The upper model P2 is the maximization model of social net benefit.The net benefit takes into account the time consumption cost of travelers and the fixed running cost.At the same time,the revenue from congestion pricing is used to subsidize buses to ensure fairness.The upper model P3 is a modification of P2.By introducing the Gini coefficient,an objective function with the Gini coefficient as small as possible and the net social benefit value as large as possible is constructed.Finally,a genetic-simulated annealing algorithm is designed.The result shows that congestion pricing has a significant effect on improving the social net benefit.Compared with the situation without congestion pricing,the social net benefit increases by 11.56%,and the social net benefit based on the Gini coefficient increases by6.59%.At the same time,the fairness of different toll levels,whether to distinguish whether the traveler time value,public transport subsidies for three kinds of situations are analyzed,the results show that the congestion pricing model based on the Gini coefficient is more helpful to find a solution that satisfies the minimum Gini coefficient and the maximum social net benefit value,and it is valuable to distinguish the time value of travelers and subsidize public transportation in order to improve the social net benefit.