Breaking into emergency shuttle service: Aspects and impacts of retracting buses from existing scheduled bus services

High-quality transit service is a vital aspect of any modern city. When unexpected interruptions to the transit service occur, they reduce the quality of service provided to the public. One of the main strategies that is employed to deal with rail service interruptions is “bus bridging,” whereby buses from scheduled services are deployed to offer shuttle services. Very few efforts are found in the literature that investigate this policy effectiveness. Therefore, this study aims at exploring the different aspects and impacts of retracting buses from scheduled services in response to subway and streetcar service interruptions in Toronto. It explores the size of the deployment, as well as the system response and recovery times using detailed subway and streetcar shuttle service reports collected in 2015. The paper shows remarkable fluctuations not only in the utilized number of shuttle service buses over time, but also on the service response and recovery times.