| As urbanization in China accelerates,the scale of urban development is expanding.Urban residents' life becomes faster and faster with increasing demand for travel.While the travel distance is increasing,requirements for travelling time become stricter.It is expected to complete the trip in a short time.As an important part of urban transportation,urban public transport is one of the main ways for residents to travel every day.Service level and operation quality of public transport have been concerned by residents and bus operators.Therefore,it is always the focus of bus system planning to improve service and operation efficiency of public transport with limited bus configuration resources and to reduce operation cost of public transport system while meeting the requirements of residents' travel.At present,the fundamental reason that affects service of public transport is imbalances between supply and demand.Only by providing differentiated services to passengers in bus routes,service for regular transit can be improved even with limited resources.With the goal of enhancing service of regular transit and reducing cost of bus operation and passenger travel,this paper analyzes the phenomenon of imbalanced distribution of passenger flow and puts forward integrated service model of public transport that combines limited-stop and short-turn service,providing differentiated service to stations and intervals with different demand for passenger flow along the bus route.Besides,with the goal of minimizing cost of passengers' travel time and bus running time,this paper proposes the optimization model of multi-service for bus which applies operation strategy of integrating limited-stop and all stop services to branching corridor,optimizing the scheme of bus frequency and limited-stop.And considering influence of random factors,with skipped-stop and short-turn as strategy,combining bus holding at the short-turn station,operation scheme of transit service is dynamically controlled.At the same time,in order to deal with the randomness of bus travel time,the paper introduces bus holding control and balance the service interval of stations,improving the adaptability and stability of transit operation services.Through in-depth discussion and research of organization optimization of bus service mode and dynamic control strategy,this paper can effectively improve bus service and reduce cost of bus operation system.The main research results and contents of this paper are as follows:(1)Research on multi-mode operation strategy for bus servesFocused on differences in the distribution of passenger flow demand along the bus route,the optimization of multi service model of public transport is proposed which allows buses travel around a certain phrase of the route and skipping operation in the stops with less flow demand,namely the limited-stop and short-turn services composition model.At the same time,in order to reduce influence of skip-stop operation on passengers,some buses run the model of all-stop service.Through analyzing influence of limited-stop service on passengers,the paper classifies passenger's demand for OD which determines passengers' demands of limited-stop service and all-stop service.With minimization of passengers' travel cost and bus operation cost as the objective,the optimization model is established for limited-stop service.At the same time,in consideration of the bus running process,running stations with short-turn service is determined based on the optimization of limited-stop service to shorten running time.With minimizing the total cost of the bus operation system as the goal,optimization model for integrating limited-stop and short turning services are proposed on the basis of short-turn service model.Based on the genetic algorithm,the optimal scheme for bus frequency and operation are output.Finally,the effectiveness of the operation strategy of bus multi-service is validated with examples.The systemic optimization method for the service mode in the single bus route can provide basis for optimization of multi bus lines in the public transport network in this part.(2)Optimization of bus combination services model for a branching corridorIn the process of optimizing bus service model,optimization method of combination of limited-stop and short-turn service mode for a branching corridor is developed with the consideration of parallel in the multi bus routes.Based on analysis of characteristics of bus routes and passenger's travel requirements under a branching corridor,a branching corridor is divided into a plurality of feeder lines and trunk lines.Considering passengers' travel characteristics and bus services of feeder lines and trunk lines,passengers' travel selection from feeder lines,trunk lines and feeder lines to trunk lines under a branching corridor is analyzed,and trunk passenger waiting time,in-vehicle time and bus running time both in feeder lines and trunk lines are calculated.Taking into consideration of the total operation costs in feeder lines and trunk lines,with minimizing the total cost of bus operation system under branching corridor as objective function and bus network vehicle size as constraints,the optimization model of multi bus line service is established for a branching corridor.And using the genetic algorithm to solve the optimization model and output the programme of line frequency and stop stations.Finally,taking the actual branching corridor as an example to optimize a number of bus routes and verify the effectiveness of the optimization model.(3)Coordinated control strategy of dynamic bus stop-skipping and short-turnThe dynamic control strategy is used to optimize the operation mode of bus stations,considering influence of the requirements' changes in passengers' flow during operation of the bus.In order to fully reflect the optimization effects of skipped-stop control and short-turn control,through effect's analysis of station with minimum passenger demand and bus capacity's influence on the control strategy,this paper selects the variable control cycle to dynamically control the bus scheduling and calculates the number of stranded passengers in four situations by analyzing stranding situation in the process of cycle evolution.Based on that,the process of bus stop-skipping and short-turn operation is simulated.In order to avoid the impact of the bus short-turn on the headway's stability of the down direction bus,the bus holding control at the short-turn station has been set.By balancing the headway of a short-turn vehicle with an adjacent vehicle in the downward direction,the calculation model of the holding time at the short-turn station is developed.According to bus' s arrival time at each station,it confirms bus' s operation time,passenger's waiting time and travel time.And with minimum of costs of passengers' waiting time,travel time and bus running time as the objective function,a coordinated optimization model of skipped-stop and short-turn is developed.Through comparison of optimization effects of different control strategies by examples,the effectiveness of the coordinated control strategy of dynamic skipped-stop and short-turn is verified.The research results of this part provide basis for the stability optimization study of bus stop service under the influence of random travel time.(4)Dynamic bus holding control strategy considering random travel timeFor the randomness of inter station travel time in regular transit line,based on the coordinated control strategy of bus skipper-stop and short-turn,the bus holding control is introduced to balance the service interval of bus stations and improve the stability of serving stations.Through analyzing evolutionary process of bus operations,arriving time and departing time of buses at stations with bus holding are determined in the process of stopskipping and short-turn.Considering the arrival of passengers within bus serving time and bus holding time,the number of stranded passengers and waiting time during holding control are calculated.To balance the service interval of stations,judgment method of bus holding control is structured and calculation model of the holding time is developed.Considering the influence of bus holding control on passengers' waiting time,in-vehicle time and bus running time,to minimize the total cost of the bus operation system,an optimization model of dynamic bus holding control is built under the strategy of stop-skipping and short-turn controls.The Monte Carlo method is used to deal with the randomness of travel time between stations.And the solution of bus operation scheme is designed based on genetic algorithm.Finally,the effectiveness of the dynamic bus stop control strategy is verified through comparative analysis of different control strategies.Aiming at optimization of operation efficiency and travel cost,an optimization model of bus multi-service mode and a dynamic bus control strategy are presented.And the validity of both model and method are proved by examples,which can provide theoretical basis for improvement of bus system planning and scheduling plan for bus operation enterprises. |
PDF Full Text Request