URBAN TRAFFIC NETWORK FLOW MODELS

Addressed in this paper are the development and comparative assessment of macroscopic network-level traffic flow models, which describe the behavior and interrelation between traffic variables defined at the network level. These variables include average speed, concentration, flow, the fraction of vehicles stopped in the network, and the two-fluid running time variables. Three alternative sets of interrelated models, each with a different starting postulate, are presented and tested in terms of their performance against a series of microscopic simulation runs corresponding to different concentration levels. In each model system, a different functional form is postulated for either the speed-concentration relation or the fraction of vehicles stopped versus concentration relation. The functional form for the other relation is then derived from the postulated model by invoking the two-fluid theory of town traffic. The models are calibrated and tested using the simulation results. The analysis indicates that the network-level traffic variables are interrelated in a manner similar to that captured by the traffic models established for individual road sections. In particular, a well-known linear speed-concentration model as well as a nonlinear alternative are found to be generally applicable at the network level.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1987/1112/1112-011.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=URBAN+TRAFFIC+NETWORK+FLOW+MODELS&author=J.+Williams&author=H.+Mahmassani&author=R.+Herman&publication_year=1987
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309044642
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Traffic Flow Theory and Characteristics. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Williams, James C
  • Mahmassani, Hani S
  • Herman, Robert
• Publication Date: 1987

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 78-88
• Monograph Title: Highway capacity and flow theory and characteristics
• Serial:
  • Transportation Research Record
  • Issue Number: 1112
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Network analysis (Planning); Stopping; Traffic simulation; Traffic speed; Traffic volume
• Uncontrolled Terms: Macroscale; Network flows; Stopped vehicles
• Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory;

Filing Info

• Accession Number: 00465549
• Record Type: Publication
• ISBN: 0309044642
• Files: TRIS, TRB, ATRI
• Created Date: Feb 29 1988 12:00AM