Development of Key Performance Indicator to Compare Regularity of Service between Urban Bus Operators

This paper evaluates options for a key performance indicator that compares differences in performance for maintaining service regularity on high-frequency routes between urban bus operators. The data used for this study were collected by the International Bus Benchmarking Group, facilitated by Imperial College London, and relate to 12 medium- to large-sized urban bus operators from different countries. Two annual rounds of data collection provided lessons on feasible data characteristics, required sample size, and data-cleaning processes. Four key performance indicator alternatives were tested. Their strengths and weaknesses are described: excess wait time; standard deviation of the difference between the scheduled and the actual headway, and two methods that show percentages of service within a fixed (wait assessment) and a relative (service reliability) number of minutes from the scheduled headway. The results suggest that whereas all four methodologies illustrate a different, interesting view on service regularity performance, the methodology for excess wait time is the best option when the key performance indicator should reflect the customer experience of the regularity of service.