Urban Mixed Traffic Network Equilibrium Analysis Under The Influence Of Taxi Services

Urban transportation network is a mixed traffic network, composed of cars, taxies, buses and so on. The taxi flow takes up a large percentage of the urban road traffic, and its service is quite different from the large-capacity public transportation and the car, so the fleet size and service behavior of taxi have a large influence on urban transportation. However, the existing network equilibrium assignment approach has less considered the influence of the taxi service on urban transportation in the mixed urban traffic network. The paper considers the influence of taxi service into the general equilibrium analysis approach for a comprehensive system research. It is expected to broaden and develop the traffic assignment theory and offer theoretical and scientific basis for establishing reasonable transportation planning and traffic management strategies.Firstly, a traffic network equilibrium assignment problem regarding taxi as a single mode of various traffic modes is studied. With the premise of the public transportation preference strategy implementation, we assume the traveler who has a car can travel by car, taxi or bus, and the other who has no car can travel by taxi or bus. The influence of the parking charge measure to traveler's traffic mode and route choice behavior is analyzed. A mixed traffic network equilibrium assignment problem is studied under the condition that parking charge measure is carried out for cars but not for taxi, using road network equilibrium model fundamental. A multi-user and multi-mode mixed traffic network equilibrium variational inequality model is established considering the parking charge measure influence. On the condition that public transportation preference strategy (the public transportation vehicles and other vehicles have an interaction) is not considered, the traveler's choice behaviors of traffic modes and routes under different values of time are discussed. Based on the BPR formula, the road travel time function of the mixed traffic network is constructed. The mixed traffic equilibrium assignment problem in the congestion network is studied using road network equilibrium model fundamental. A multi-user and multi-mode mixed traffic network equilibrium variational inequality model without considering the public transportation preference strategy is established and a hybrid solution algorithm which is based on diagonalization and MSA is designed for solving the model.Secondly, according to the traveler's uncertainty risk manner to the road network, the traveler can be divided into three species: risk-averse travelers, risk-prone travelers, and risk-neutral. In the degradation road network, the taxi multiclass user traffic mode and the route choice behavior are analyzed, and the variational inequality model equaling with the equilibrium condition is established, then an efficient algorithm is designed for solving the model. The numerical experiment indicates there is a large difference between different risk manner travelers for their choices of the traffic mode and the route in the degradation road network. Moreover, the traffic management measure is also different to the different risk manner traveler effectiveness's influence.Thirdly, considering the different influence of the parking charge on the taxi manner and the normal manner, the urban taxi network service equilibrium problem under the parking charge influence is studied, and a combinatorial mathematics planning model is established with two equilibrium sub-problems considered simultaneously. One equilibrium sub-problem is described as a combined network equilibrium model, which is used for describing the route choice behavior of occupied taxi and normal traffic and the equilibrium assignment distribution characteristics of the traffic flow of vacant taxi with the interaction of various traffic modes and elastic demands in the road network. The other is described as a set of linear and nonlinear equations, which guaranty that the relation between taxi waiting time and the passenger waiting time, the balance between customer demand and taxi supply, and the taxi service time conservation equation are satisfied. The waiting time of each traffic area with a certain taxi service size and a parking charge level can be obtained by the model. It can offer theoretical basis for ensuring reasonable taxi service size.Finally, based on that empty taxi driving search behavior is decided by the travel time arriving at the target area and the customer demand distribution characteristic together, and introducing the concept of searching attraction radius, supply and demand balance relations of the taxi service network under condition of the fixed customer demand are analyzed, and the urban taxi network equilibrium model with the demand distribution influence is established, and the iterative solution algorithm is designed according to the model structure characteristic. Using numerical experiment, the passenger waiting time in each traffic area with different taxi service size is calculated. The model can provide scientific guidance and academic reference for urban taxi network service planning and management.