The origin-destination matrix estimation problem: analysis and computations

For most kind of analyses in the field of traffic planning, there is a need for origin-destination (OD) matrices, which specify the travel demands between the origin and destination nodes in the network. This thesis concerns the OD-matrix estimation problem, that is, the calculation of OD-matrices using observed link flows. Both time-independent and time-dependent models are considered, and also study the placement of link flow detectors. When a time-dimension is considered, the estimation problem becomes more complex. Besides the problem of distributing the travel demand onto routes, the flow propagation in time and space must also be handled. The time-dependent OD-matrix estimation problem is the subject for two studies. The first is a case study, where the conventional estimation technique is improved through introducing pre-adjustment schemes, which exploit the structure of the information contained in the OD-matrix and the link flow observations. In the second study, an algorithm for time-independent estimation is extended to the time-dependent case and tested for a network from Stockholm, Sweden. Finally, the underlying problem of finding those links where traffic flow observations are to be performed is studied, in order to ensure the best possible quality of the estimated OD-matrix. There are different ways of quantifying a common goal to cover as much traffic as possible, and this study creates an experimental framework in which they can be evaluated. Presupposing that consistent flow observations from all the links in the network yields the best estimate of the OD-matrix, the lack of observations from some links results in a relaxation of the estimation problem, and a poorer estimate. The study formulates the problem to place link flow detectors as to achieve the least relaxation with a limited number of detectors.

Language

  • English

Media Info

  • Pagination: 48p
  • Serial:
    • Issue Number: 1102

Subject/Index Terms

Filing Info

  • Accession Number: 01386826
  • Record Type: Publication
  • Source Agency: ARRB
  • ISBN: 9789185831951
  • Files: ATRI
  • Created Date: Aug 22 2012 9:50PM