Research On Single-route Bus Departure Frequency Optimization And Timetable Scheduling

With the accelerating process of urbanization, the externalities of traffic problemshave been escalated as well. More and more people have realized that publictransportation play a key role in solving urban traffic problems. The relevant departmentsalso have introduced some laws and regulations of bus priority to make this kind ofconcept implemented. During conventional public traffic operation and scheduling, staticbus scheduling mainly concern the determination of bus headway and the preparation ofthe bus timetables. This paper mainly discusses how to determine the optimal departurefrequency during the bus operating period, under the conditions of a given passengerdemand, and then make a bus timetable based on it.Firstly, this paper introduces the meaning and classification of conventional busschedule, in order to make sure of the object and scope of this study. Then it introduces thegeneral principles and the basis of the schedule preparation, and describes some key issuessuch as the passenger flow data survey, the relationship between departure intervals anddeparture frequency. Then four classic models of departure frequency determination havebeen introduced and improved considering the road running status. However, these modelscannot express the relationship between the interests of passengers and bus companiesclearly. According to the deficiency of these methods, as well as combining with thepresent research of domestic and foreign countries, this paper comes up with a newoptimization model of departure frequency based on minimizing the expected total cost ofa single bus. This model divides the operation time of one day into several periods thathave equal length of time according to passenger flow rule, and considers the impact ofdetermination of departure frequency on passenger cost and bus company cost.Considering each departure of a bus as a process, this model takes the waiting time, ridingtime, delay time and comfort level of passenger as passengers cost. Bus company costcontains operation cost and fixed cost. Then, the model puts the two costs together througha weighting method to get the total cost of one departure. Multiply the result by thedeparture frequency of this time period and then we can receive total costs of every timeperiod. The goal of this model is minimizing the total costs. Thus we can acquire optimaldeparture frequency of each time period. Next, the model is verified on basis of passenger flow data of521bus line in Wuhan. Comparing the results with other methods, we findthat this model can significantly reduce the total cost of passengers and improve the totalsocial benefit, and the selection of variable quantity and parameter is comprehensive andrealistic. Finally, we make some alternative timetables for521bus line by using theoptimal departure bus frequency. In comparison with the original schedule, the optimizedtimetable remarkably reduces the total departure trips and the minimum fleet size in astatistical period, which further demonstrates the applicability of the model.