A study in which the dynamic assignment model 3DAS was used as a planning tool is described. The Virginia part of the Washington, D.C., metropolitan area was chosen for the study. This area offers a heavily congested urban network with several rerouting possibilities. On the basis of available data it was decided to calculate a morning peak hour from 5:00 until 11:00 a.m. in 24 periods of 15 min each. The results show that the use of dynamic assignment for planning purposes can be very helpful. Dynamic assignment gives more detailed information than static assignment methods about the occurrences of traffic jams, and a more precise location and cause of congestion can be identified. Advanced traffic management system measures, introduced to alleviate the congestion, can be simulated, and all kinds of evaluations are possible, such as influences on travel time and jam length and effects of ramp metering and rerouting. Dynamic assignment, however, requires more accurate data and more computing time. Also very important is the ability to visualize the results. A dynamic assignment model gives flows in time. The best way to analyze the results is to present them in a movielike fashion. This requires a computer with a powerful graphics capability. For advanced traffic management systems to be successful more data and better (three-dimensional) origin-destination matrices are needed. New methods for origin-destination estimation and data from more induction loops and probe vehicles will improve the reliability of the results.


  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 100-109
  • Monograph Title: Travel demand modeling and network assignment models
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00670489
  • Record Type: Publication
  • ISBN: 0309055245
  • Files: TRIS, TRB
  • Created Date: Dec 23 1994 12:00AM