The Economic Value of Timetable Changes
Eric Kroes, Significance, Andrew Daly,
Little is known about the consumer value of changes in service frequency for timetable-based transport systems. We propose and illustrate an appropriate specification for individual travellers and methods to obtain estimates of total welfare.
Values of travel time savings and of reliability are widely available for use in appraisal studies, but much less is known about the consumer value of changes in service frequency for timetable-based transport systems such as bus, train, ferry and air transport. In practical studies often “average waiting times” are computed as half the headway, and multiplied by an assumed value of waiting time. But this is not a realistic reflection, and does not result in correct estimates. The issue is that services interact, both temporally and geographically, so that headway is often not the best measure of the impact of service frequency on travellers.
In our paper we use theoretical reasoning, complemented with a review of empirical studies, to propose an appropriate specification of the different impacts of timetable changes for individual travellers. We also address the issue of how to aggregate these values across the travelling population to obtain estimates of total welfare. In some cases, when there is significant variation in preferences, logsum-type measures are used to derive expected utilities. In other cases it may be more appropriate to use mean utilities. The ‘rooftops’ model (Tyler and Hassard, 1973) gives a useful procedure for averaging services on a single line.
We illustrate the application of the method for rail services, and demonstrate how the key model parameters influence the results. The paper concludes by providing some recommendations on the practical use of the methodology. While the application is specific to the rail sector, the results are expected to be of interest for other medium and long-distance transport services and possibly for other economic sectors.
Tyler, J. and Hassard, R. (1973): Gravity/elasticity models for the planning of the inter-urban rail passenger business, Proceedings of Seminar G, PTRC Summer Annual Meeting, University of Sussex.
Association for European Transport