Evaluation With Improvement Of Level Of Service For Urban Rail Transit Lines

With the continuous improvement of economic development,the level of service of the urban rail transit system has attracted more and more attention.The traditional level of service research mainly focuses on the selection of construction standards at the design level.However,at the operational level,due to the strong differences in the time and space dimensions of the all-day passenger demand of the city,the train load of the urban rail transit line is greatly unbalanced,which affects the passenger service experience.Starting from the operation level,this paper first analyzes the connotation and influencing factors of the level of service of the urban rail transit,then proposes the evaluation method of line level of service from the perspectives of train load space-time difference and passenger travel process,and finally studies the improvement measures of the level of service based on the train operation plan.The main work and conclusions of this paper are as follows:(1)Based on the current research on the level of service,the level of service factors of urban rail transit lines are mainly divided into two aspects: travel comfort and travel efficiency.The qualitative and quantitative methods are used to analyze the parameter characteristics of the relevant level of service influencing factors.The research shows that travel efficiency is determined by the factors at the line design level,and the train congestion reflects the line operation service quality to a certain extent.In this paper,the train load is proposed as the main factor to evaluate the level of service,and the differentiated classification method of the line level of service is discussed.(2)A classification method of the level of service for urban rail transit lines based on spatio-temporal load difference is proposed.Firstly,the section train load is taken as the basic element of the line load.Considering the average level and distribution deviation characteristics of the line load in the study period,the line load level is described by indexes of mean value and coefficient of variation,and the calculation method is established.Then,the method of classifying the line level of service by using the mean value and coefficient of variation under the multiple time-space points is studied.Finally,the spatial-temporal distribution of line load and the level of service of several urban rail transit lines of a certain city are analyzed and evaluated,and the threshold values for classifying the level of service under case conditions are obtained.The results show that,while the line level of service is affected by the average load,a higher degree of load imbalance may reduce the line level of service.The space-time points with low service level can be divided into two categories: the overall high line load and the uneven distribution of line load.The mean value index of the former is0.80～0.92,and the coefficient of variation index is 0.32～0.42.The mean value index of the latter is 0.42～0.75,and the coefficient of variation index is 0.36～0.71.(3)Considering that congestion has a great impact on the feeling of passenger level of service,from the whole process of passengers’ trip,a method for evaluating the level of service of the lines based on the in-vehicle passenger satisfaction is proposed.Based on the estimation method of the number of passengers in the vehicle,the in-vehicle passenger satisfaction model based on the proportion of crowded passengers and the average number of crowded sections experienced by crowded passengers in the time-space point is established.The relationship between the in-vehicle passenger satisfaction index and line level of service is defined.Through the case analyses of the impact of train congestion threshold and normalized parameters on the in-vehicle passenger satisfaction,the distribution of line service level of the multiple time-space points based on the in-vehicle passenger satisfaction index is analyzed.The case analyses show that,compared with the method of using the maximum train load to evaluate the line level of service,considering the proportion of crowded passengers and the number of crowded sections during the trip process,the impact of a small number of passengers or the short congestion experience on the evaluation of the level of service is weakened.The analyses of influencing factors of the in-vehicle passenger satisfaction show that the train congestion threshold determines the calculation range of crowded passengers,and has a great impact on the classification of line level of service.The distribution of line level of service of multiple space-time points conforms to the trend that the smaller the mean value indexes are,the larger the coefficient of variation indexes when the level of the space-time points is the same.(4)The train operation organization methods to improve the line level of service are studied.An optimization model of operation scheme is established to improve the in-vehicle passenger satisfaction and reduce the average waiting time of passengers,the train running mileage and the coefficient of variation of the line load.The effects of the number of departure trains,train routing,and departure headway optimization on the objective function of the model and the classification of level of service are analyzed.The influence of improving the space-time evenness of load on the level of service of the line is analyzed.The case analyses show that the optimization of train routing can reduce the operation cost without significantly reducing the level of service when the the number of departure trains remains unchanged.The optimization of departure headway is an effective measure to improve the level of service.The uneven departure mode reduces the proportion of crowded passengers from 39.0% to 24.3%,and the in-vehicle passenger satisfaction index can be improved by 35.4%.Under the uniform departure mode,when the number of departure trains is increased by 5,the number of crowded passengers is reduced to 0.When considering the optimization of departure headway,the number of departure trains is increased by 3 to reduce the number of crowded passengers to 0.The improvement effect of the departure headway optimization measures on the level of service is related to the passenger flow scale.The case studies show that when the maximum average train load factor of the sections does not exceed the train congestion threshold,the improvement of the line load evenness can reduce the degree of train congestion.However,when the overall passenger flow is overloaded,improving the load evenness of the line may increase the number of crowded trains and passengers.When the maximum average train load factor of the sections approaches the limit of train load,adjusting the departure headway can no longer improve the line level of service.At this time,it is necessary to improve the capacity of the whole line.