Diffusion Characteristics Of Traffic Demand Extreme Spillover And Service Station Planning Method Of Bicycle Sharing System

Urban bicycle sharing system(Bicycle Sharing System,BSS)has extended the last road of public transportation,and it is a green and low-carbon way of travel,which is becoming more and more popular both at home and abroad.However,the phenomenon of extreme state which caused by large traffic demand and unbalance of time and space has been the main bottleneck of the development of shared bicycles.Research on the diffusion characteristics of service station traffic demand extreme spillover,and according to the user’s travel demand,service station are set up and the capacity are planned scientifically,which can provide guarantee for the realization of bicycle sharing system.On the basis of studying the diffusion characteristics of BSS traffic demand extreme spillover,micro unit method for the layout of service stations of bicycle sharing system is established,and the initial capacity planning algorithm and the capacity planning hourglass model of the service station are also studied.At last,the data analysis system of space-time running of shared bicycles is designed and developed,which provides a reference for the actual management of shared bicycles.The main research work in this paper is as follows:(1)The characteristics of traffic demand diffusion and the rule of extreme spillover between adjacent service stations are analyzed.Improved the SIR epidemic model,a T-SIR diffusion model and algorithm of BSS traffic demand extreme spillover is proposed.Considering the characteristics of the manual duty service station,the T-SIR is improved again,and the T-SIRH diffusion model and algorithm of BSS traffic demand extreme spillover is put forward.The comparative analysis shows that setting up the manual duty service station is helpful to prevent the spread of extreme spillover.The example shows that the model can simulate the extreme spillover process of BSS,and provides a decision reference for the formulation of BSS emergency management plan;(2)Through the analysis of BSS traffic demand diffusion process,the diffusion characteristics of traffic demand extreme spillover meet the requirements of using the micro unit method to the characteristics of the unit is proved.According to the operation characteristics of BSS,using the principle of micro unit method,through establishment of the service area of geometric model,mesh,element analysis,system integration,introduced the boundary conditions and solved regional demand strength,a micro unit method for the layout of BSS service stations is established.The practice proved that micro unit method can effectively analyze the unbalance of BSS’s unit supply and demand,and provide reference for the layout of the service station;(3)The method of micro cell estimation suggests that the new service station should be build or the capacity of the established service stations should be improved where the imbalance of supply and demand in the large range.In view of the new service station,an initial capacity planning model of service station with high applicability is proposed.Improving Multi-logit,the share rate calculation model of bicycle designed;according to the different sources of travel demand,took into account the distance between the location of each kind of travel demand and service station,the actual rental and returned demand of bicycle station are got;the daily turnover of the typical service stations is analyzed,and the initial capacity of the shared bicycle service station is planned.In view of improve the service station,the hourglass model of the shared bicycle service station capacity planning was established.According to the historical rental and returned data,it is ensured that the separate service stations can meet the needs of rental and returned the shared bicycles in the operation period,and get the most basic requirement of the service station capacity.Proposed and defined the unbalance coefficient of rental and returned demand imbalance and unbalance coefficient of net rental and returned demand.Combined with the most basic requirements of service station capacity,got the minimum planning capacity of service station.The example shows that after arranging an scheduling every 30 minutes during the peak period,there are 83.3% and 87.5% service periods can meet users’ traffic demand respectively,reaching the realization of bicycle sharing system basically.(4)Took Hangzhou City Xiasha service area bicycle sharing system as the case,based on the construction of traffic demand extreme spillover diffusion model,micro unit method for setting up service station,service station capacity planning model,designed and developed the spatial and temporal data analysis system which based on the browser / server(B/S)architecture,and detailed display of function module,operation process and results analysis.