TESTS ON A HEURISTIC ALGORITHM FOR A COMBINED ATC- ASSIGNMENT PROBLEM

This paper was presented at Session 33 - Area Traffic Control. This paper investigates the feasibility of achieving optimal solutions for a combined area traffic control (atc) and assignment problem under different testing conditions. A sequential combination of a signal optimisation program, TRANSYT, and a traffic assignment program, ARRBTRAFIC, is adopted. Signal settings obtained from TRANSYT are used to derive non-decreasing delay functions suitable for obtaining either user-optimal or system-optimal flow patterns from ARRBTRAFIC. The new flow pattern obtained after assignment is fed bact to TRANSYT to form an iterative procedure. Based on a test network, the results indicate that there is only a small difference between user-optimal and system-optimal traffic assignments, and that equilibrium solutions depend on initial conditions. These solutions are therefore not global optimal solutions. The existence of local minima can be attributed to a positive feedback mechanism inherent in atc. A combined atc-assignment problem becomes a non-convex problem if this positive feedback dominates the re-routing effect of traffic assignment. (TRRL)

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 213-220
  • Serial:
    • Volume: 9
    • Issue Number: 5

Subject/Index Terms

Filing Info

  • Accession Number: 00309188
  • Record Type: Publication
  • Source Agency: ARRB Group Ltd.
  • Files: ITRD, TRIS, ATRI
  • Created Date: May 21 1980 12:00AM