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Traffic sensor having piezoelectric sensors which distinguish lanes

  • US 5,486,820 A
  • Filed: 12/18/1992
  • Issued: 01/23/1996
  • Est. Priority Date: 12/18/1992
  • Status: Expired due to Fees
First Claim
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1. A traffic sensor for sensing the number of vehicles travelling in each lane of a predetermined portion of a roadway, comprising:

  • a piezoelectric sensor stretched across a width of said predetermined portion of said roadway, said piezoelectric sensor generating an electrical signal when deflected by a vehicle, generated electrical signal having a first polarity when deflected by a vehicle in a first lane of said roadway and a second polarity when deflected by a vehicle in a second lane of said roadway; and

    means for discriminating the polarity of said generated electrical signal and for determining from the respective polarities in which lane of said roadway said piezoelectric sensor has been deflected by one of the vehicles.

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