Multi-modal Urban Traffic Structure Regulation Method For Integrated Network

The rapid growth of urbanization and motorization has led to the spread of traffic congestion in major cities of China.Traffic control measures that deals with various specific problems discovered in the traffic state fail to overcome difficulties in essence,putting management implementations into a passive.In order to mitigate traffic congestion from the source and improve the service level of the corresponding supply and demand structure,it is necessary to regulate travel demand by traffic structure regulation strategy concerning transport resource allocation and policy intervention to reduce individual motorized travel while encourage the use of public transportation.Due to the systematic feature and complexity of urban transportation,the relationship between elements in the system is complicated.Therefore,the paper abstracts the elements to analyze their causal relationships influencing the evolution of the urban transport structure.On the basis of the system feedback and policy control mechanism,a system dynamics model of urban traffic structure evolution and policy regulation is established,followed by the study of the system state description,control target determination and traffic structure regulation theory and method.The results realize the intelligent and systematic decision-making on traffic management to essentially mitigate urban traffic congestion,as well as to promote the application of system dynamics in the field of traffic engineering which enriches the theory of system dynamics.Based on the structural characteristics of multi-modal transportation network,the study proposes an integrated traffic network topology method and travel cost calculating method of a multi-modal trip.A topology for multi-mode network layers and mode conversion network is given which overcomes the defects that the mode conversion segment topology is too complex to apply to larger network.Setting the origin and destination points at the pedestrian network layer,the generalized cost of mode conversion between different modes and within the same mode are taken into consideration to form the multi-modal trip cost function.Drawing on the system dynamics,the system elements involved in the travel demand subsystem,the travel cost subsystem,the network state subsystem and the policy intervention subsystem are selected and their causal relationship are quantified.Besides,the system target and the traffic structure evolution logic are explained.The multi-mode traffic user equilibrium(MSUE)model based on C-logit traffic assignment method is adopted to describe the loading of the traffic structure on the network.Taking passenger-kilometer as the traffic structure evaluation index and network private car loading as the control target,the system dynamics model for urban traffic structure regulation is established.Focusing on the private car restrictions policy based on the last digit of license plate numbers and the private car purchase restriction policy,the study proposes the control target determination method and control threshold selection method considering the first-order material delay of system,and analyzes the short-term action mechanism and long-term joint action mechanism of the two policies.By conducting the topology of a network according to the core area of Hangzhou,the feasibility of the evolution model is verified.With the control method simulated and deduced,policy mechanisms are revealed and regulation strategy is discussed.