Non Monotonicity of Path Travel Time in Dynamic Traffic Assignment: Implications for Solution Existence and Practical Algorithms

As dynamic traffic assignment tools and applications become more widespread, it is important to better understand the mathematical properties of these models and the implications for solution methods and their real-world application. Existence of an interior equilibrium solution to dynamic assignment problems and convergence to such a solution has been predicated on the assumption of the monotonicity of the path travel time function—considered to be a mild assumption though not formally challenged or tested in the literature. This paper shows that most realistic representations of traffic dynamics in a traffic assignment model are likely to result in violations of the monotonicity assumption. This is done first through a simple example in an idealized network, intended to show the traffic mechanism that leads to such violations in a general network. Next, numerical experiments are conducted on three real world networks. The study shows that non monotonicity of path travel time is quite likely in realistic models of general urban networks. Implications for algorithm development and practical application are discussed.


  • English

Media Info

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

Subject/Index Terms

Filing Info

  • Accession Number: 01155182
  • Record Type: Publication
  • Report/Paper Numbers: 10-4097
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 12:06PM