The path size factor revisited: an alternative derivation

Piet Bovy, Shlomo Bekhor, Carlo Giacomo Prato

Research output: Contribution to journalJournal articleResearchpeer-review


The Path Size concept attempts to capture correlations among routes in route choice modeling, by including a correction term in the multinomial logit formulation. Several correction terms were proposed in the literature, yet no satisfactory derivation based on theoretical arguments is presented, thus rising doubts about the correct specification of the correction terms. This paper proposes the detailed and systematic derivation of a new formulation of the Path Size measure, and explicitly defines the assumptions involved in its derivation. The Path Size Correction (PSC) factor results from the notion of aggregate alternative as well from the simplification of Nested Logit models. The new Path Size measure offers a more natural interpretation of the correlation due to spatial overlap of alternative routes. Estimation of PSC-Logit models in two real-world networks and calculation of predicted choice probabilities in synthetic networks allow the comparison of the new Path Size measure with respect to the classical one. Estimates show similar performances between the models, and predictions illustrate better performances of the new version of the Path Size factor.
Keyword: Route choice, Path Size Logit, Multinomial Logit, discrete choice, model estimation, Path Size Correction
Original languageEnglish
Book seriesTransportation Research Record
Issue number2076
Pages (from-to)132-140
Publication statusPublished - 2008
Externally publishedYes


  • Engineering
  • Transportation


Dive into the research topics of 'The path size factor revisited: an alternative derivation'. Together they form a unique fingerprint.

Cite this