COMBINED EQUALIBRIUM IN A NETWORK WITH PARTIAL ROUTE GUIDANCE

In this paper the conditions are investigated under which a combined assignment of drivers pursuing user equilibrium and drivers seeking to achieve a system optimum can be carried out. Such a situation could occur with a route-guidance system that advises system optimum routes, with only a partial take-up of advice. Through a theoretical analysis it is found that under the assumption of a polynomial flow-delay function, the resulting combined flow pattern is unique and stable. This combined equilibrium can be found through a diagonalisation approach, in which iteratively the system optimum and the user equilibrium is calculated for the relevant group of drivers. However, such a route pattern consists of a number of used routes for the user equilibrium drivers, and a number of different routes for the system optimum drivers, with at most one route in common. Because of the nature of each group, the user equilibrium drivers will use minimum costs routes, whilst the guided system optimisers will be routed via minimum marginal cost routes, with equal or higher real costs. Using a simple example, the solution to the combined assignment problem is illustrated; special attention is paid to the various characteristics of the flow pattern, particularly in relation with the level of take-up of guidance. An important finding is that in this example a large proportion of guided drivers is needed before the resulting route pattern will differ from the original user equilibrium. Only with a very high level of take-up can a system optimum be obtained at the individual expense of some of the guided drivers. In such a situation there are drivers that can improve their individual travel costs by unilaterally changing routes. For the covering abstract of the conference see IRRD 832076.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/093920441X
• Corporate Authors:

  Engineering Foundation

  United Engineering Center, 345 E 47th Street
  New York, NY  United States  10017
• Authors:
  • VAN VUREN, T
  • Van Vliet, D
  • Smith, M J
• Publication Date: 1990

Language

• English

Media Info

• Pagination: p. 375-87
• Serial:
  • TRAFFIC CONTROL METHODS. PROCEEDINGS OF THE FIFTH NG FOUNDATION CONFERENCE, SANTA BARBARA, CALIFORNI
  • Publisher: Engineering Foundation

Subject/Index Terms

• TRT Terms: Decision making; Driver information systems; Itinerary; Mathematical models; Networks; Optimization; Roads; Traffic assignment; Travel
• Uncontrolled Terms: Guidance; Optimum; Road networks
• ITRD Terms: 2248: Decision process; 9104: Guidance; 699: Itinerary; 698: Journey; 6473: Mathematical model; 679: Traffic assignment
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00607207
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• ISBN: 0-939204-41-X
• Files: ITRD, TRIS
• Created Date: Mar 31 1991 12:00AM