Analysis Of Urban Traffic Demand Management Based On Tradable Credits Schemes

Urban traffic is a complex and huge system.Travelers are the subject of the system.Their behavior will affect the operation of the system.Traffic demand management measures will affect the traveler behavior directly or indirectly.On the other hand,traveler behavior will also have an impact on the decisions of traffic planners.Therefore,the researches on traveler behavior and traffic demand management are important for urban traffic planning and management.Based on the management tool-tradable credits,this dissertation analyzes the laws of interaction between the traveler behavior(mode choice behavior,route choice behavior and trip chain choice behavior)and traffic demand management from the angles of quantity and public pricing.The traffic system will achieve the expected traffic network flow by controlling tradable credits.Specifically,the main contents of the dissertation are summarized as follows:(1)Quantity-based tradable credits scheme is introduced into bi-mode traffic system analysis.In order to realize the system optimization and ensure the efficiency of tradable credits scheme",an optimization model is built by cotrolling tradable credits and bus investment.The costs of car user and bus passenger are given and the mode equilibrium between car and bus is discussed.The scale economies of transit system are explored.At last,the ratio of car,bus investment and credit price with different credits schemes are analyzed in the numerical example.The case while the traffic planner has a requirement on the ratio of bus travelers is also considered.(2)Quantity-based tradable credits schemes are extended to multi-mode network from two-mode network.Congestion pricing and tradable credits are analyzed from the angle of the social welfare and consumer surplus.The utility functions of three modes(car,bus and bike)are analyzed respectively under congestion pricing,tradable credits scheme and no any management measure.Accordingly,three schemes' models are constructed with the purpose of maximizing the social welfare.The optimal bus fare,congestion pricng and tradable credtis scheme are obtained by solving the model.Results show that congestion pricing would earn more social welfare than the other traffic measures.However,tradable credit scheme will make travelers earn more consumer surplus than congestion pricing.(3)Quantity-based tradable credits shemes are incorporated into trip chain network analysis.Trip chain network equilibrium conditions are given.An aggregate model which is equal to the trip chain network equilibrium conditions is proposed to describe the traveler behavior.The convexity,equivalency and uniqueness conditions of the model are discussed.Based on the integrated model,a bi-level programming is designed in which the upper level tries to maximize the social welfare by appropriate tradable credits,and the lower level is the trip chain network equilibrium.Also,an expanded network is developed to eliminate the non-additivity of the utilities of activities and travelling in the trip chain network.The Simulated Annealing(SA)method is designed to solve the proposed bi-level model.At last,two cases are used to test the validity of the model.(4)Price-based tradable credits schemes are explored in this section.Firstly,the possible problems of quantity-based tradable credits schemes in practice are analyzed.A public pricing-based tradable credits sheme is proposed to overcome the defects of quantity-based tradable credits schemes.A public pricing mechanism-marginal cost pricing is analyzed.Marginal cost pricing is proved be rational by a mathematical method.Based on the public pricing-based tradable credits scheme,the user's route choice behavior and credits trading behavior are analyzed.By comparing with the optimal congestion pricing,the optimal price-based tradable credits scheme is obtained.(5)The public pricing-based tradable credits scheme is applied to the park-and-ride design in the monocentric linear city.A discrete optimization model is proposed to locate the multi-P&R facilities.The trading behavior among travelers with different modes is analyzed.Taking the Lanzhou traffic network as an example,the effects of the new tradable credits scheme,bodily congestion in transit carriages and P&R facilities'investment on social cost,traveler behavior and P&R locations are investigated.