This report compares and evaluates the traffic assignment results from five assignment techniques: all-or-nothing, stochastic multipath, iterative, incremental, and equilibrium. The results of the assigned volumes from the five techniques are compared to ground counts. Various statistical measures are used to evaluate the results. Five different assignments of the existing Tyler, Texas, network were compared to ground counts to detemine if there were differences among the results. Measures of how well the assignment reproduces traffic counts were divided into two groups: macro-level measurements (screenlines, cutlines, and VMT) which are network-wide analyses and micro-level measures which are link-by-link comparisons. No significant difference was found among the five assignment techniques when using macro-level measures. The values for the incremental assignment had the best results compared to ground counts when using micro-level measures. Some of the statistical measures were affected by the introduction of capacity restraint. Otherwise, it was concluded that the incremental and the equilibrium assignments represented a slight improvement from the all-or-nothing and the stochastic multipath assignments. However, the difference in results was not significant enough when using capacity restraint to warrant the extra cost such as link capacity data and computer run time involved in the capacity-restraint assignments. This implies that much of the precision in the assignment procedure using the different techniques may be sacrificed and still produce acceptable assignment results.

  • Supplemental Notes:
    • Research study title: Improving the Efficiency and Responsiveness of the Traffic Assignment Process.
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  United States  76011

    Texas State Department of Highways & Public Transportation

    Transportation Planning Division, P.O. Box 5051
    Austin, TX  United States  78763

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Chang, D M
    • Dresser, G B
  • Publication Date: 1990-8

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 62 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00605601
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-90/1153-3, Res Rept 1153-3, TTI: 2-10-89-1153-3
  • Contract Numbers: Study 2-10-89-1153
  • Created Date: Mar 31 1991 12:00AM