Study On Multi-mode Bus Frequency Allocation Based On Stop Demand Elasticity

With the development of economy and the speeding up of urbanization,the number of motor vehicle increases gradually,traffic congestion and environment pollution become serious increasingly.Priority to the development of public transport becomes the first choice of big cities to ease traffic congestion and environmental pollution.As the important component of city public transportation,the service level of conventional public traffic affects the attractiveness of public transportation and must be optimized reasonably.Transit lines are the skeleton of the bus network,once formed less changes.But bus frequency determines the operational efficiency of the whole bus system and the service level of the whole transport system.It is necessary to make reasonable regulation according to the different bus passenger flow demand.In the process of bus operation,there are two aspects,supply(company)and demand(passenger),and the two sides of are interactive.How to reasonably determine the frequency to coordinate the passengers and operating company interests of both parties is a key problem for transit operations management.Based on the full analysis of passenger demand changes of public transport,this paper introduces the concept of bus stop demand elasticity and uses the departure interval and bus size of bus service pattern as decision variables to build a two-objective optimization function,which minimizes passenger travel time and maximizes net operational cost at the same time under the constrains of operational cost,fleet size,headway,bus capacity and passenger number.Then combines the two models with time value and weights into the finial model to minimize system cost and examines the correctness and effectiveness with Lingo software.The paper designs genetic algorithm for the public transit system cost minimization model constructed before,forms initial population under the constrains of headway,passenger number,waiting time,operational profit and bus capacity,uses the optimal preservation strategy and monte carlo method to select operation to speed up the convergence.Then,carry out numerical example test,the results show that the model can reduce the passengers' waiting time,reduce passenger travel time cost,improve the interests of the company,maintain the number of passengers.Finally,compare the results of bus frequency allocation model under the background of the different elasticity of demand and clear the influence of different elastic on the bus frequency allocation.