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Fuzzy logic traffic signal control system

  • US 5,357,436 A
  • Filed: 10/21/1992
  • Issued: 10/18/1994
  • Est. Priority Date: 10/21/1992
  • Status: Expired due to Term
First Claim
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1. A method of controlling a traffic signal at an intersection, comprising the steps of:

  • providing a microprocessor connected to the traffic signal;

    defining control parameters of cycle time, phase split, and offset time for the traffic signal;

    generating data of traffic flow through the intersection and a neighboring intersection, said data including direction of dominant traffic flow through the intersection and degree of saturation on competing approaches to the intersection;

    characterizing said traffic flow data using membership functions;

    applying fuzzy logic decision rules to said characterized traffic flow data; and

    adjusting said traffic signal control parameters based on said fuzzy logic decision rules applied to said characterized traffic flow data, including the steps of adjusting said phase split to reduce the difference between saturation on said competing approaches to the intersection, adjusting said cycle time to maintain a desired degree of saturation on one of said approaches having the highest saturation, and adjusting said offset time incrementally to improve traffic flow in said dominant direction.

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