Public Bus Transit Travel Time Variability in Ankara (Turkey)

Abstract

This study investigates the variability of public bus transit travel times in Ankara, Turkey, and examines the underlying causes. The city’s public transit system is predominantly bus-based, operated by both public and private sectors, and typically shares road space with other traffic, making it highly susceptible to travel time fluctuations. Organized in a hub-and-spoke structure centred on Ulus and Kızılay, the system’s performance was analysed through three models, addressing variation across operational regions, trunk roads, and individual lines. Two sub-models were also developed using standard deviation and coefficient of variation as dependent variables. The analysis identifies three main causes of travel time variability: temporal factors, spatial factors, and service characteristics. Results confirm that all these dimensions significantly influence variability. The study concludes that the current uniform system organisation needs restructuring to reduce travel time variability and improve service reliability.