Modeling And Empirical Research On Bus Bunching Adjustment Strategies Under Dynamic Road Conditions

As a green mode of transportation,public transportation plays an important role in alleviating urban traffic congestion and promoting urban sustainable development.However,urban bus routes are often affected by a variety of external factors in actual operations,causing fluctuations in bus-to-station intervals at bus stops,resulting in bus bunching phenomenon and seriously affecting bus service quality.This paper took urban conventional public transportation as the research object.Based on the basic assumption that the running time between adjacent stations is dynamic,but the rule is known according to the historical data,the two adjustment strategies of bus bunching problem under dynamic road condition and dynamic demand condition were discussed.Through case study,the basic assumptions and the two adjustment strategies were verified and analyzed,so that the proposed strategy can provide theoretical guidance and decision support for the daily management and operation of the bus enterprises.The main work and innovation of this paper are as follows:(1)The strategy model of departure interval adjustment of departure station under dynamic conditions was established.The objective is to balance the arrival interval and passenger capacity,thus to reduce or even avoid the occurrence of bus bunching from the source.At the same time,the compass search algorithm,was improved,and the multi-round constrained compass search algorithm was proposed.The multi-round constrained compass search algorithm was used to solve the model.Then,through numerical examples,the sensitivity of the algorithm and the results of the model were analyzed.The results show that the proposed model can effectively balance the arrival interval and passenger capacity of the bus.(2)A combined adjustment strategy model of departure and holding under dynamic conditions was established.For long bus lines,only adjusting departure interval at the departure station can not meet the actual operational needs.Therefore,considering the combination of station control strategies to optimize the modeling,through strategy comparison,it was found that the holding strategy has obvious advantages in the applicability and so on.Therefore,the combined holding strategy was considered for modeling.The model was solved by the multi-round constrained compass search algorithm.Through numerical examples,the algorithm and adjustment strategy were realized.The results show that the combined adjustment strategy has better effect in the application of long lines.(3)Taking Beijing Te-9 outer road bus line as an example,the basic assumptions of the proposed hypothesis are verified,and two adjustment strategies are analyzed.Based on the data of the running time between adjacent stations and IC card,combined with bus line information and bus station information,the outliers were identified by boxplot method,the missing values were supplemented by interpolation method,and the changing rules of dynamic road condition and dynamic demand were obtained by median method,which provides data support for case verification.Based on the case data,two adjustment strategies were analyzed,and the optimal departure timetable,the holding control points and the holding time were obtained.The results show that the proposed adjustment strategy can reduce or even avoid the phenomenon of bus bunching.