FREEWAY RAMP CONTROL USING FUZZY SET THEORY FOR INEXACT REASONING

This paper presents a fuzzy controller for freeway ramp metering, which uses rules of the form: IF "freeway condition" THEN "control action." The controller has been designed to consider varied levels of congestion, a downstream control area, changing occupancy levels, upstream flows, and a distributed detector array in its rule base. Through fuzzy implications, the inference of each rule is used to the degree to which the condition is true. Using a dynamic simulation model of conditions at the San Francisco-Oakland Bay Bridge, the action of the fuzzy controller is compared to the existing "crisp" control scheme, and an idealized controller. Tests under a variety of scenarios with different incident locations and capacity reductions show that the fuzzy controller is able to extract 40 to 100 per cent of the possible savings in passenger-hours. In general, the fuzzy algorithm displays smooth and rapid response to incidents, and significantly reduces the minute-miles of congestion.

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  • Corporate Authors:

    Pergamon Press, Incorporated

    Headington Hill Hall
    Oxford OX30BW,    
  • Authors:
    • Chen, L L
    • May, A D
    • Auslander, D M
  • Publication Date: 1990-1

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  • Accession Number: 00492281
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Mar 31 1990 12:00AM