Substitutability as a spatial concept to evaluate travel alternatives

Bert van Wee*, Sander van Cranenburgh, Kees Maat

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)
69 Downloads (Pure)


In this paper we propose the concept of ‘substitutability’, which we define as the extent to which the preferred travel alternative can be substituted by other initially less preferred alternatives. This is particularly of interest when the preferred alternative is no longer available, e.g. due to labour strikes, weather conditions, power failures, etc. Travel alternatives in this context can comprise of activities, modes, time of day, and routes. We argue that substitutability is a promising new concept, which is relevant for travel behaviour research. In particular, substitutability is relevant from an accessibility perspective, as well as from the perspective of ‘freedom of choice’. In this paper we conceptualise the concept of substitutability, present a mathematical expression for it and discuss its relationships with other related concepts in the travel behaviour research field, such as the freedom of choice, accessibility, and robustness/reliability. We illustrate the concept of substitutability using a case study, where we look at the extent to which airports can be substituted by other airports, and by high-speed railway stations, conditional on a given destination, namely the cities of Paris, London and Frankfurt. Finally, we present a research agenda.
Original languageEnglish
Article number102469
Number of pages12
JournalJournal of Transport Geography
Publication statusPublished - 2019

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.


  • Accessibility
  • Airports
  • High-speed rail
  • Research agenda
  • Substitutability


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