Optimization Strategies Of Bus System Operation Reliability Under Different Line Types

As a vigorously promoted sustainable transportation,the bus system reduces passengers’ satisfaction due to the unstable running time and the difficulty of predicting the arrival time.Under the diversified development of cities,bus lines are diversified.The bus running time also fluctuates greatly under different route types,which causes difficulties in bus scheduling and inconvenience for passengers to travel.At present,the improvement of reliability is mainly considered from the road sections or stations,and less from the characteristics of different line types and the environmental implication.Therefore,the paper analyzes the operation characteristics and reliability influencing factors of different types of bus lines,the joint optimization strategy of limited-stop bus service and speed regulation,and the optimization strategy of hybrid bus system considering the fuel life cycle.The paper firstly analyzes the line operation attributes and passenger flow demand of different line types of buses in Beijing.Then,the operation characteristics of different line types of buses are analyzed from the line running time,the running time per unit distance of the road section,and the headway between stations.Finally,various regression methods are used to analyze the reliability influencing factors of different line types of buses.The results show specific differences in bus operation characteristics and reliability factors under different line types.Secondly,the alternative station sets of limited-stop bus services are obtained based on the influencing factors of bus reliability of different bus line types.Taking the minimization of bus operation cost,passenger travel cost,and reliability cost as the objective function and considering the operation process of limited-stop bus service and all-stop bus service and the calculation of headway,the paper constructs a joint strategy optimization model for different bus lines which includes limited-stop bus service and speed regulation.The model is constructed to determine the limited-stop bus station,the departure time,and the running speed of all buses.The genetic algorithm is used to solve the model.The case analysis shows that the limited-stop bus service strategy is beneficial in reducing the operating cost of the bus system.The speed regulation strategy can better reduce passenger travel cost and reliability.The joint strategy can reduce the bus system’s various costs,including the operating cost,passenger travel cost,and reliability cost.Finally,based on the hybrid operation system of electric buses and fuel buses,the carbon emission is considered including fuel life cycle and the influence of speed,acceleration,and load.Taking the minimization of bus operation cost,passenger travel cost,reliability cost,and carbon emission cost as the objective function,the paper constructs a joint strategy optimization model for the speed regulation and limited-stop bus service considering the carbon emission of the fuel life cycle.The limited-stop bus station,the departure time,and the running speed of all buses are determined.Genetic algorithms are used to solve the model.The results show that the joint strategy optimization model and the joint strategy optimization model considering the carbon emissions of the fuel life cycle can greatly reduce the total cost of the bus system.The former has a more prominent effect on reducing passenger travel cost and reliability cost,while the latter can significantly reduce the carbon emissions generated from the bus.