Modeling And Analysis Of Inter-regional Transit System Integration

Nowadays,the integration of urban and rural and the formulation of urban agglomeration have become important trends of regional economic development in China.The traditional administrative region economy is slowly replaced by urban agglomeration economy.Under this background,the space range of people's economic,cultural and social activities is expanding.The fragmented cross-border transit services lead to unnecessary transfers,which increase the passengers' travel time and transit fare.In order to adapt to meet the needs of people's various travel activities in big cities and urban agglomerations,it is necessary to establish a convenient and rapid inter-regional transit service system,which needs the coordination and integration among multiple local transit systems.In recent years,there has been an increasing level of interest in improving the optimization and coordination of transit services among many cities and regions around the world.For example,Foshan and other cities in China have allocated some integrated transit lines across the jurisdictional borders.These lines adopt a cooperation mode of unified numbering,joint operation,territorial management and respective settlement.They greatly facilitated people's inter-regional travel by transit.Based on the operation characteristics of transit systems in China,this paper formulates optimization models to quantitatively study a series of problems in the integrated transit service,such as the behaviors of local operators,the intervention measures of local authorities,and the passengers' response to transit services in the process of inter-region transit coordination and optimization.The main study work can be summarized as follows.(1)Considering the operational characteristics of traditional local transit system in China(the existence of inter-regional barriers),the existing practice of inter-regional transit system integration(the elimination of inter-regional barriers)and the relationship between the local operators(cooperation and competition),this paper models four kinds of integration modes from the view of transit operators to optimize the operation of inter-regional transit system.The four modes are:inter-regional barriers-competition,inter-regional barriers-cooperation;no inter-regional b arri ers-cooperation;no inter-regional barriers-competition.Based on an inter-regional integrated transit line in Foshan city,this paper conducts a numerical study,and compares the consumer surplus,the operators' profits and the social welfare under various strategies.The numerical studies show that,in order to facilitate the passengers and maximize social welfare,the transit authorities should take measures to break down the jurisdictional barrier between different regions and prompt operators to compete with each other on the inter-regional transit line which is jointly operated by different local operators.(2)Considering the commonweal nature of public transport,based on the optimal operator mode in the first part(no inter-regional barriers-competition),this paper studies how transit authorities use transit subsidies to guide the competitive behaviors of transit operators to reduce the social cost.The passenger cost is an important part of the social cost.In order to measure the passenger cost more accurately,a congestion function is proposed to describe the in-vehicle crowding discomfort based the pedestrian flow theory.Specifically,based on the inter-regional integrated transit line in Foshan city,a variational inequality model is used to investigate the competitive behaviors of transit operators in oligopolistic competition transit market with fixed demand between two regions.A bi-level optimization model is proposed to describe how transit authorities use transit subsidies to guide the competitive behavior of transit operators in social welfare maximization transit system.By analyzing and comparing the performances of the integrated transit system in oligopolistic competition market and social welfare maximization market,numerical studies show that the competition mechanism should be made full use of and transit subsidy is an important regulation means that should be valued by the transit authorities in the integrated transit system.(3)Considering the passengers' response to the generalized transit cost,the integrated transit system models with fixed transit demand are extended to further investigate the inter-regional transit system integration practices in Foshan and other cities in China.With elastic transit demand,a maximization model is proposed to describe the competitive behavior of transit operators in oligopolistic competition transit market,and the nonlinear complementarity problem equivalent to this maximization problem is also given.Based on the nonlinear complementarity problem in oligopolistic competition market,an optimization model with nonlinear complementary constraints is proposed to describe how transit authorities use transit subsidies to guide the competitive behavior of transit operators in social welfare maximization transit system.Moreover,by the introduction of elastic demand function,the effects of pricing and subsidy on the performances of inter-regional integrated transit system is discussed.Numerical analysis further reveals the effects of competition mechanism and transit subsidy on the performances of the integrated transit system and points out that the transit authorities should reasonably use the pricing and subsidy to manage the inter-regional transit system by trading off the interests of operators and passengers,as well as their own financial situation and objectives.(4)Under more general market conditions,this paper studies the optimal subsidy problem in the integrated transit system across the jurisdictional borders by proposing optimization models.Firstly,the market conditions of the first three part are extended as follows:1)The competition between auto and bus is considered;2)The operators can use different types of vehicles to provide different quality of service;3)The decision variable of bus operators are transit fare and frequency;4)Passengers make their travel choice based on their perceived generalized travel cost.Next,a variational inequality model is proposed to describe the oligopolistic competition market,in which the operators compete with each other to maximize their own profits.An optimization model is proposed to describe the social optimum market,in which the operators cooperate with each other to maximize the social welfare.Finally,by analyzing the existence and uniqueness of the solution and the equilibrium condition of two models,the optimal transit subsidy,which can make the oligopolistic competitive achieve the social optimal result,is determined.The numerical studies verify the validity of the proposed models.The results show that the optimal subsidies in oligopolistic competition market reduce the ticket price,increase the system frequency and guide the operators to achieve a social optimum.