Bi-objective routing problem with asymmetrical travel time distributions

Xu Zhang, Mei Chen

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Recent studies have confirmed that travelers consider travel time reliability in addition to average travel time when making route choice decisions. In this study, we develop a bi-objective routing model that seeks to simultaneously optimize the average travel time and travel time reliability. The semi-standard deviation (SSD) is chosen as the reliability measure because it reflects travelers' concerns over longer travel time better than the commonly used standard deviation. The Pareto-optimal solutions to the bi-objective model are found by using an improved strength Pareto evolutionary algorithm. Tests on a real-world urban network with field measured travel time data have demonstrated good performance of the algorithm in the aspects, such as computational efficiency, quick convergence, and closeness to the global Pareto-optimal. Overall, the bi-objective routing model generates reasonable path recommendations. The SSD-based model is sensitive to the asymmetry of travel time distribution and tends to avoid paths with excessively long delays. This would be particularly helpful to those users placing high values on travel time reliability.

Original languageEnglish
Pages (from-to)87-98
Number of pages12
JournalJournal of Intelligent Transportation Systems: Technology, Planning, and Operations
Issue number2
StatePublished - Mar 4 2018

Bibliographical note

Publisher Copyright:
© 2018 Taylor & Francis.


  • bi-objective
  • path finding
  • travel time distribution
  • travel time reliability

ASJC Scopus subject areas

  • Software
  • Information Systems
  • Aerospace Engineering
  • Applied Mathematics
  • Control and Systems Engineering
  • Automotive Engineering
  • Computer Science Applications


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