Optimizing Fleet Composition and Size under Uncertainty in Urban Transit Systems

The goal of this project was to study the fleet sizing problem in the context of an urban transit system with several unique features: (1) a fleet with a heterogeneous mixture of vehicles; (2) integrated decision support, including acquisition, retirement, and allocation decisions over multiple time periods; and (3) various uncertainties regarding demand for origin-destination (OD) pairs and vehicle efficiency. Over the course of a one-year grant effort, the researchers first developed a deterministic optimization model to minimize the total fleet acquisition and operation costs for all time periods within the planning horizon. Then, a two-stage stochastic programming (SP) model was devised to explicitly cope with uncertainty. The model minimizes the expected total costs by optimizing (1) the here-and now fleet acquisition and retirement decisions in the first stage and (2) the allocation recourse decisions in the second stage after the random parameters are realized. The research team collaborated with a local third-party logistics (3PL) company in St. Louis, Missouri, who provided real world data for this project. Computational studies were conducted to show the benefit of the two stage SP model by comparing it to the deterministic model using point estimates of random parameters.

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  • Supplemental Notes:
    • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
  • Corporate Authors:

    University of Missouri, St. Louis

    College of Business Administration
    One University Boulevard
    St. Louis, MO  United States  63121

    Midwest Transportation Center

    2711 South Loop Drive, Suite 4700
    Ames, IA  United States  50010-8664

    Iowa State University, Ames

    Institute for Transportation
    2711 South Loop Drive, Suite 4700
    Ames, Iowa  United States  50010-8664

    U.S. Department of Transportation

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Authors:
    • Li, Haitao
    • Pan, Deanna
  • Publication Date: 2018-3


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final report
  • Features: References;
  • Pagination: 26p

Subject/Index Terms

Filing Info

  • Accession Number: 01681351
  • Record Type: Publication
  • Contract Numbers: Part of DTRT13-G-UTC37
  • Created Date: Jul 18 2018 9:37AM