BILEVEL OPTIMISATION OF TRANSPORTATION NETWORKS

The need to reduce traffic congestion is becoming increasingly important. The means of achieving this aim involve optimising parameters such as traffic signal green-times, road prices and public transport fares. This paper will describe a new bilevel method of optimising traffic signals and prices. The method uses the steepest descent direction together with projections in order to define a descent direction which will reduce the objective function subject to the overriding necessity to be in equilibrium. The paper will provide a description of the bilevel method together with results on two simple problems. Optimisation is performed on two functions simultaneously; the equilibrium function E (which must have value zero for equilibrium) and the objective function Z which is minimised subject to the constraint that E is zero. For most traffic problems equilibrium is not mathematically well behaved and therefore the method approaches equilibrium in stages. At each stage it minimises Z while avoiding the difficult equilibrium region.

Language

  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 29-36

Subject/Index Terms

Filing Info

  • Accession Number: 00763008
  • Record Type: Publication
  • ISBN: 0080434304
  • Files: TRIS
  • Created Date: Apr 9 1999 12:00AM