Application of the MORPC Microsimulation Model for User Benefit Evaluation of Transit Projects

The Federal Transit Administration (FTA) has rigorous requirements for travel demand models used to estimate user benefits of New Starts transit projects. These requirements are based on the general methodology of user benefit (UB) calculation as the difference between total composite utilities calculated before and after the project introduction. The current FTA approach limits the corresponding scope of choices (over which the composite utility is calculated) to mode and route choices. The new generation of activity-based (AB) tour-based microsimulation models, of which the Mid-Ohio Regional Planning Commission (MORPC) model is one, requires a certain reconsideration of the user benefit calculations in view of the more complicated structure, where trip distribution and mode choice stages are closely intertwined as well as because of the fully-disaggregate (individual record) structure of the output. A constructive way is proposed to adjust the tour-based model output to the requirements of the UB calculation procedure. To meet the FTA guidance, the tour model structure should be constrained in the most appropriate way where some of the sub-models should be identified as fixed (supposed to run only once for the “base” alternative) while some other ones are supposed to be re-run fore each alternative including “base” and “build”. The sub-models that are re-run also represent a source for the UB calculation. The ways it can be done with AB models are discussed. The method finally adopted for the MORPC model is based on a “fixed tour table” with UB calculated at the entire-tour mode choice level that includes 6 main tour mode alternatives. Additionally, for using the FTA software Summit, the microsimulation model output in the individual-tour-record format with a great variety of travel segments and person/household attributes should be converted into a standard file with a single record for each origin-destination pair and limited number of segments. This is not a trivial transformation with respect to the mode utilities. A theoretically sound algorithm for utility aggregation was developed that preserves the mode choice probabilities and logsums exactly. With this algorithm, an output of a microsimulation model becomes directly comparable to output of a conventional aggregate model. Application experience of the developed methodology and tools for Columbus, Ohio, North Corridor Transit Project, a combined Alternatives Analysis and Draft Environmental Impact Statement project, is discussed.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; Maps; References; Tables;
  • Pagination: 21p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01047019
  • Record Type: Publication
  • Report/Paper Numbers: 07-0935
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 5:31PM