Bus Bunching and Variability of Travel Speed and Dwell TimeA Bus Service Study of ‘The Orbiter’

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Transportation Engineering
Degree name
Master of Engineering in Transportation
Publisher
University of Canterbury. Civil and Natural Resources Engineering
Journal Title
Journal ISSN
Volume Title
Language
Date
2012
Authors
Ryan, Grace Elizabeth
Abstract

The context of this study is the increasing need for public transport as issues over high private vehicle usage are becoming increasingly obvious. Public transport services need to compete with private transport to improve patronage, and issues with reliability need to be addressed. Bus bunching affects reliability through disruptions to the scheduled headways. The purpose of this study was to collect and analyse data to compare how travel time and dwell time vary, to explore the variation of key variables, and to better understand the sources of these variations. The Orbiter bus service in Christchurch was used as a case study, as it is particularly vulnerable to bus bunching. The dwell time was found to be more variable than travel time. It appeared the Canterbury earthquake had significantly reduced the average speeds for the Orbiter service. In 1964, Newell and Potts described a basic bus bunching theory, which was used as the basis for an Excel bus bunching model. This model allows input variables to vary stochastically. Random values were generated from four specified distributions derived from manually collected data, allowing variance across all bus platforms and buses. However the complexity resulted in stability and difficulty in achieving convergence, so the model was run in single Monte Carlo simulations. The outputs were realistic and showed a higher degree of bunching behaviour than previous models. The model demonstrated bunching phenomena that had not been observed in previous models, including spontaneously un-pairing, overtaking of buses delayed at platforms, and odd-numbered bunches of three buses. Furthermore, the study identified areas of further research for data collection and model development.

Description
Citation
Keywords
traffic, transport, public transport, reliability, bus bunching, travel time, dwell time, the Orbiter, Newell and Potts
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Grace Elizabeth Ryan