An investigation is reported of the sensitivity of the results of traffic assignments to the inputs from proceding modeling phases. The analyses of the assignment results produced by different trip matrices provide a means of evaluating the sensitivity of various commonly used measures of assignment accuracy. A better-worse approach was used in developing data for anayzing the sensitivity of the measures of accuracy of traffic assignments. The four stochastic matrices used in the analyses are defined, the analyses are outlined, and the evaluation and interpretation are discussed. Comments are made on the implications relative to the origin-destination trip tables. The study found that due to the aggregative nature of the assignment procedure, many of the differences observed at the zonal and zonal interchange levels tend to disappear in the assignment results. This implies that much of the precision in the preceding modeling phases (i.e. trip generation and trip distribution phases) can be sacrificed while still producing resonably accurate assignment results. Therefore, abbreviated or sketch planning techniques should produce assignment results of sufficient accuracy for valid evaluation and comparison of system alternatives.

Media Info

  • Features: Figures; References;
  • Pagination: p. 50-52
  • Monograph Title: Passenger travel demand forecasting
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00157830
  • Record Type: Publication
  • ISBN: 0309025850
  • Files: TRIS, TRB
  • Created Date: Sep 28 1977 12:00AM