Variation in bus transit service: understanding the impacts of various improvement strategies on transit service reliability

Abstract

Transit agencies wishing to offer reliable service with less variability compared to schedules face several challenges, encouraging them to employ various strategies. While previous research has considered the effects of various strategies on running time, there has been little effort to understand their impacts on reliability of service. This article examines the impacts of various improvement strategies, implemented by Société de Transport de Montréal (STM) along one of its heavily utilized bus routes, on running time deviation from schedule, variation in running time, and variation in running time deviation from schedules. These strategies have been implemented at different time points over past 3 years. They include, chronologically ordered, implementation of a smart card fare collection system, operation of a reserved bus lane, introduction of limited-stop bus service, use of articulated buses, and operation of transit signal priority (TSP). This study uses automatic vehicle location (AVL) and automatic passenger count (APC) systems at the bus route segment level of analysis. The introduction of a smart card fare collection system increased bus running time and service variation. Articulated buses, limitedstop bus service and reserved bus lanes have mixed effects on variation in comparison to the running time changes, while TSP did not show an impact on variations in our study. This study offers transit agencies and schedulers a better understanding of the effects of various strategies on different aspects of service variation, which are important components of transit service reliability.

Individual and Synergetic Effects of Transit Service Improvement Strategies: Simulation and Validation

“…For 57 example, Schwartz et al (1982) found that during peak-hour, bus speed increased by 83% and 58 bus reliability increased by 57 percent while traffic speed on the relevant street increased by 10 59 percent. In contrast, Diab and El-Geneidy (2013) found that while the operation of an exclusive 60 bus lane had a modest effect on reducing bus running time by 2.7%, travel time variability 61 increased by 0.5% due to the effect of right turning vehicles. Their study analysed empirically a 62 mix of measures to improve transit performance in Montreal using automated vehicle location 63 (AVL) and automated passenger counts (APC) data with a focus on reliability.…”

Modelling reliability and distribution of travel times in transit

“…Strategy assessment (operators) 4.6.1 Diab and El-Geneidy (2013) studied the impacts of various improvement strategies on service reliability and concluded that the strategies can decrease the standard deviation of travel time. Assuming the current service travel time distribution follows a 3-components GMM model (GMM3), the parameters for the GMM3 model are set as …”

“…These strategies include smart fare card collection system, reserved bus lanes, limited-stop bus services, stop consolidation, articulated buses and transit signal priority. Diab and El-Geneidy (2013) further investigated the impact of the implementation of various strategies on service variations.…”

“…Instead of using traffic flow to represent traffic conditions, some studies have defined congestion levels using actual travel times and free flow travel times (Gilliam et al, 2008;Peer et al, 2012 Given a set of regression models, most studies estimated the coefficients equation-byequation using the classical OLS (Diab and El-Geneidy, 2013;. However, Martchouk et al (2010) argued that formulating separate ordinary and the standard deviation of travel time would leave out potentially important cross-equation correlation that would result in inefficient parameter estimates.…”

“…It captures the patterns of travel times in a way that allows direct comparisons across different times, routes and indicators. This variation measure provides a key piece of information for identifying unreliability causes and understanding impacts of various improved strategies on transit service reliability (Diab and El-Geneidy, 2013). …”