Research On Location Optimization Of Transfer Point Under Combined Travel Conditions Of Bicycle And Bus

The rapid development of urban transportation makes people's travel more convenient,but at the same time it also generates a lot of traffic problems,such as traffic jam,which seriously restrict the sustainable development of the social economy.The advent of shared bicycles makes bicycles widely used,which has improved traffic congestion and environmental pollution.However,bicycles are limited by the travel distance.In short-distance travel,travelers can complete a trip by bicycles.But in long-distance travel,travelers must use bicycles to transfer to public transport for a trip.The study of traffic assignment provides a theoretical basis for solving the main problems in urban traffic and the formulation and implementation of traffic planning strategies.However,the research on bicycle travel is obviously not perfect.On the one hand,the time and price factors are usually considered when constructing the generalized cost function in the existing traffic assignment model,but the influence of travel distance is ignored.On the other hand,in recent years,the rise of shared bicycles has led to a gradual increase in bicycle travel,but the planning of bicycle transfer facilities is not perfect enough.On the basis of these,the following two aspects are researched.Firstly,according to the characteristics of urban traffic multimodal travel in our country,a method of constructing multimodal traffic super network model is proposed,and the generalized cost function considering the distance factor of arcs and paths is constructed.Based on this,the traffic assignment model is established.Secondly,a bicycle transfer station location modal based on the multimodal traffic assignment model considering the distance factor and bi-level programming is proposed.The influence of bicycle transfer location planning on social benefit is studied.The main contents of this paper are as followed.(1)According to the characteristics of various modes in urban multimodal transport system,considering the transfer behavior,the travel process of the travelers in the multimodal network is divided into four stages:boarding,driving,transfer and leaving.According to the theory of graph theory and super network,the structural characteristics of multimodal traffic system are analyzed,the method of constructing urban multimodal traffic super network model and the general representation of each element in the network are proposed in this paper.On the basis of these,the super-path,sub-path and efficient super-path in multimodal traffic super network is defined.(2)Based on the four stages of travel process,the generalized cost function of arcs and paths considering the distance factor is constructed from three elements of time,price and comfort.Based on the sub path cost,the improved shortest path and efficient path search algorithm is proposed.At the same time,based on the stochastic user equilibrium,the corresponding traffic assignment model and algorithm is proposed,and a numerical example is used to illustrate the feasibility and validity of the model and algorithm.The solution results show that the travel distance has an important influence on the traveler's travel choice.The travel distance is an indispensable factor in the study of the traveler's travel behavior.(3)Considering the social benefit,a bicycle transfer station parking spots location bi-level programming model is established in this paper.The social benefits include two main aspects:traffic congestion and pollution emissions.The upper model is a discrete location model,and the lower model is a stochastic user equilibrium model.Based on the improved path search algorithm and traffic assignment model,genetic algorithm is used to solve this problem,a numerical example is used to illustrate the feasibility and validity of the model and algorithm,and the result and parameter sensitivity are analyzed.The example shows that the bicycle transfer point should not be set randomly,nor is it that the more it is built,the better.Too many parking spots will cause waste of resources and reduce the efficiency of the entire transportation system.A reasonable layout will maximize the benefits of the entire system.