Research On The Optimization Of Feeder Bus Network With Speed Difference

With the continuous development of economy and the advancement of urbanization,traffic congestion has become a difficult problem for large and medium-sized cities in China.In order to ease traffic congestion,China will further implement the development of urban public transport,especially rail transit.The rail transit has a fast transportation speed and strong carrying capacity,and it is not affected by the surrounding traffic environment.However,the excessive construction cost and long construction period has restricted its wire mesh density.To exert rail transit effectiveness and attract more passengers,further improvement of the rail transit connection method is needed.The main function of the feeder bus is to pick up passengers for rail transit.Ignoring the layout of feeder bus lines will inevitably affect the full function of rail transport advantages.The bus routes of the feeder bus,which mainly exsit the urban roads,are greatly affected by the surrounding road environment.Therefore,this paper carries out research on the optimization of the transport line network and aims to solve the problem of the layout of the transport bus line in the case of traffic congestion.The paper first elaborates on the basic concepts of the feeder bus.Based on the analysis of the space-time characteristics of bus operations,a probability distribution of vehicle speed based on duration statistics was established to simulate the difference in bus operating speed under actual traffic conditions.Based on the classic FBNDP(feeder bus network design problem)model,an optimization model of the transit bus line network considering the speed difference is constructed to minimize passenger costs,operator costs,and social costs,combining the FBNDP model with the probability distribution of vehicle speeds.The LINGO software is used to solve the small scale of 6 sites.The accuracy of the model was verified.In view of the complex calculation and large amount of computation of the wire-net model,an improved genetic algorithm based on the evolution reversal operation was designed for the transit bus network optimization model considering the speed difference in this paper.Finally,on the basis of the optimization model of the transit bus network considering the speed difference and the improved genetic algorithm,the examples of six stations and 54 stations are analyzed.The results show that the model established in this paper can effectively avoid the length of congested roads and reduce the total cost;the algorithm designed in this paper has a short solution time and good stability.By comparing the genetic algorithm results of six sites with the results of LINGO,the effectiveness of the genetic algorithm is verified.The comparison between the route plan and the total cost under different speeds shows that there is nodal speed,and when the speed of the congested area is lower than the nodal speed,the vehicle choosing to bypass congested areas saves money;Also,there are deviations in the route plan that does not take into account congestion speeds,the average frequency of departures is low in the actual traffic environment,and passengers spend a long time in the car.