A mean-variance approach to mixed strategies for dispatching problems under travel time uncertainty

Takeshi Nagae, Shin'ichi Sasaki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This study provides a mixed strategy model for fleet dispatching problems under travel time uncertainty. We assume a dispatcher, who assigns a fleet of vehicles to the set of route of a given single origin-destination pair. As the travel time of each vehicle fluctuates, the average travel time per vehicle becomes uncertain and its moments are determined by the vehicle assignment. In this situation, the dispatcher can achieve a smaller ATT variance without increasing its mean by using mixed strategies rather than pure strategies. We first formulate the mean-variance routing problem, whose solution is the mixed strategy that achieves the smallest variance amongst alternatives whose mean does not exceed a given upper bound. We then show that this problem can be rewritten as a quadratic programming problem using only link-based variables. This enables us to solve the dispatching problem without resorting to exhaustive route enumeration.

Original languageEnglish
Title of host publicationProceedings of the 14th HKSTS International Conference
Subtitle of host publicationTransportation and Geography
Pages189-196
Number of pages8
Publication statusPublished - 2009 Dec 1
Externally publishedYes
Event14th HKSTS International Conference: Transportation and Geography - Kowloon, Hong Kong
Duration: 2009 Dec 102009 Dec 12

Publication series

NameProceedings of the 14th HKSTS International Conference: Transportation and Geography
Volume1

Other

Other14th HKSTS International Conference: Transportation and Geography
CountryHong Kong
CityKowloon
Period09/12/1009/12/12

ASJC Scopus subject areas

  • Transportation

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