A Cell-based Merchant-Nemhauser Model for the System Optimum Dynamic Traffic Assignment Problem

Using a simple piecewise linear exit-flow function, a cell-based variant of the Merchant-Nemhauser (M-N) model is proposed for the system optimum (SO) dynamic traffic assignment (DTA) problem. Once augmented with additional constraints to capture cross-cell interactions, the model becomes a linear program that embeds a relaxed cell transmission model (CTM) for traffic propagation. The proposed cell-based M-N model is different from the existing CTM-based SO-DTA models in that (1) it does not require intersections to be standard merge and diverge; and 2) it does not directly solve for cell-to-cell flows. Generally, the proposed model has a simpler constraint structure and is easier to construct. Path marginal costs are defined using a recursive formula that involves a subset of multipliers from the linear program. This definition is then employed to interpret the necessary condition, which is a dynamic extension of the Wardrop's second principle. An algorithm is presented to solve the flow holding back problem that is known to exist in many existing SO-DTA models. A numerical experiment is conducted to verify the proposed model and algorithm.


  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 24p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01155616
  • Record Type: Publication
  • Report/Paper Numbers: 10-0367
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 10:12AM