Finding the most reliable path with and without link travel time correlation: A Lagrangian substitution based approach

Tao Xing, Xuesong Zhou

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Path travel time reliability is an essential measure of the quality of service for transportation systems and an important attribute in travelers' route and departure time scheduling. This paper investigates a fundamental problem of finding the most reliable path under different spatial correlation assumptions, where the path travel time variability is represented by its standard deviation. To handle the non-linear and non-additive cost functions introduced by the quadratic forms of the standard deviation term, a Lagrangian substitution approach is adopted to estimate the lower bound of the most reliable path solution through solving a sequence of standard shortest path problems. A subgradient algorithm is used to iteratively improve the solution quality by reducing the optimality gap. To characterize the link travel time correlation structure associated with the end-to-end trip time reliability measure, this research develops a sampling-based method to dynamically construct a proxy objective function in terms of travel time observations from multiple days. The proposed algorithms are evaluated under a large-scale Bay Area, California network with real-world measurements.

Original languageEnglish (US)
Pages (from-to)1660-1679
Number of pages20
JournalTransportation Research Part B: Methodological
Volume45
Issue number10
DOIs
StatePublished - Dec 2011
Externally publishedYes

Keywords

  • Lagrangian relaxation method
  • Path travel time reliability
  • Reliable route
  • Shortest path algorithm

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Transportation

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