Quantifying Reliability of Transit Service in Zurich, Switzerland

Abstract

Transit operators aim to provide high levels of reliability because reliable services not only are more attractive for their current and potential customers, but can also reduce operating costs by making more efficient use of resources. This work addresses the issue of service reliability in a context in which high-quality transit is the norm, not the exception. An ongoing study uses automatic vehicle location (AVL) data to estimate quantitative service reliability measures of a bus line in Zurich, Switzerland. In-vehicle observations during peak periods and aggregate operational data reports complement the AVL data. Four time profiles (morning and late afternoon peaks, between peaks, and late evening) were used to characterize transit service reliability at the route and stop level. A set of conventional operator-perspective measures (travel time, speed, punctuality, and regularity) was enhanced with a customer-oriented measure (passenger waiting time) to link service reliability to passenger waiting cost. Results indicate that the best service reliability for travel time, regularity, and passenger waiting time metrics is achieved during late night services. Services between peak hours perform better in punctuality metrics.