Balancing Reliability and Efficiency in Urban Public Transport Timetables: A Passenger- and Operator-Oriented Multi-Criteria Evaluation

Abstract

This research developed a set of quality indicators to evaluate and compare public transport timetables from both passenger and operator perspectives. The methodology was applied to the HTM urban public transport network in The Hague using three tram lines with different operating characteristics: Lines 4, 9, and 19. Planned and realised operational data, together with passenger data from Automatic Vehicle Location (AVL) and Automatic Fare Collection (AFC) systems, were used.
Traditional timetable evaluations rely primarily on operator-oriented measures such as punctuality, which do not fully capture passenger experience. From a passenger perspective, service disruptions, irregular headways, and schedule deviations increase waiting and in-vehicle travel times, reducing service attractiveness. At the same time, measures that improve service reliability often increase operational costs through additional vehicle hours or fleet requirements. However, improved operational performance can also reduce financial penalties associated with delays, early departures, and cancellations. This study addresses the limited integration of passenger and operator perspectives in timetable evaluation by translating both into measurable quality indicators.
Passenger performance is represented through reliability and efficiency indicators. Passenger Reliability (PR) measures additional travel time caused by service variability, while Passenger Efficiency (PE) reflects the relationship between travelled distance and scheduled travel time, accounting for both in-vehicle and waiting time. The operator perspective is represented through Operator Robustness (OR), based on performance-related penalties, and Operator Expenses (OE), based on operational costs associated with vehicle hours and fleet size.
The indicators were applied to a series of alternative timetables created by modifying layover time, trip time, and service frequency. OE and PE were calculated directly from timetable characteristics, whereas PR and OR required simulation of realised operations. The simulation model was based on empirical distributions derived from realised data, including initial delays, driving times, and cancellation probabilities.
Increasing trip times and layovers generally improved passenger reliability and operator robustness, while increasing service frequency produced the greatest improvements in passenger efficiency by reducing waiting times. These improvements, however, were typically accompanied by higher operational costs. Although similar trends were observed across all lines, the effectiveness of timetable modifications depended on line characteristics. For example, increasing layover time produced the largest reliability improvements on Line 4, whereas increasing trip times was generally more effective on Lines 9 and 19. Even small increases in trip time proved beneficial on Line 9 without substantially increasing costs, while larger increases improved reliability further but also increased early departures more noticeably.
The timetable alternatives were compared using a multi-criteria decision analysis (MCDA). The preferred timetable depended strongly on the selected weighting scheme. Based on literature, Passenger Reliability was recommended to receive three times the weight of Passenger Efficiency, whereas no general recommendation was made for the relative weighting of passenger and operator objectives because this depends on policy priorities. For HTM, which operates under the Metropoolregio Rotterdam Den Haag (MRDH), greater emphasis on passenger objectives was considered appropriate.
The study is limited by the range of timetable modifications considered and several modelling assumptions, including the exclusion of passenger behavioural responses and transfers. Future research could incorporate these aspects together with more detailed holding strategies. Overall, the proposed framework provides a transparent approach for evaluating public transport timetables by explicitly balancing passenger impacts and operational constraints.