Preferences for travel time under risk and ambiguity: Implications in path selection and network equilibrium

J. Qi, M. Sim, Defeng Sun, X. Yuan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)


© 2016 In this paper, we study the preferences for uncertain travel times in which probability distributions may not be fully characterized. In evaluating an uncertain travel time, we explicitly distinguish between risk, where the probability distribution is precisely known, and ambiguity, where it is not. In particular, we propose a new criterion called ambiguity-aware CARA travel time (ACT) for evaluating uncertain travel times under various attitudes of risk and ambiguity, which is a preference based on blending the Hurwicz criterion and Constant Absolute Risk Aversion (CARA). More importantly, we show that when the uncertain link travel times are independently distributed, finding the path that minimizes travel time under the ACT criterion is essentially a shortest path problem. We also study the implications on Network Equilibrium (NE) model where travelers on the traffic network are characterized by their knowledge of the network uncertainty as well as their risk and ambiguity attitudes under the ACT. We derive and analyze the existence and uniqueness of solutions under NE. Finally, we obtain the Price of Anarchy that characterizes the inefficiency of this new equilibrium. The computational study suggests that as uncertainty increases, the influence of selfishness on inefficiency diminishes.
Original languageEnglish
Pages (from-to)264-284
Number of pages21
JournalTransportation Research Part B: Methodological
Publication statusPublished - 1 Dec 2016
Externally publishedYes


  • Ambiguity
  • Network equilibrium
  • Path selection
  • Price of Anarchy
  • Risk

ASJC Scopus subject areas

  • Transportation

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