Features that Affect Variability of Travel Time on Bus Rapid Transit Systems

One of the most difficult aspects of attracting ridership on a bus system is the variability in travel time. Bus rapid transit (BRT) systems have attempted to improve on typical local and express bus systems by adding and enhancing features of the system and thereby improving travel time variability. Typical BRT features such as running way, passing capability, station spacing, use of transit signal priority, frequency of buses, use of level boarding, and the fare collection process have been described as improving reliability or variability in travel time. However, limited analysis has been performed to validate that assertion. This paper discusses which enhanced features of a BRT system will affect variability of travel time between peak hour and non-peak hour. To measure variability in scheduled end-to-end travel times, a ratio of average peak-hour travel time to average non-peak-hour travel time was compared across BRT systems. To determine the significance in the difference between these averages, a permutation test was conducted. Three of the seven considered features had a significant p-value, with a significance level of .05. The features that proved to be most significant were those dealing directly with general purpose traffic of a BRT system. Features connected more closely with the station portion of the BRT system were found to have little significance.