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Method and apparatus for determining the covering on a road surface

  • US 4,745,803 A
  • Filed: 09/08/1986
  • Issued: 05/24/1988
  • Est. Priority Date: 09/09/1985
  • Status: Expired due to Term
First Claim
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1. A method for determining road surface conditions, comprising the steps of:

  • inputting a measurement signal to a pair of spaced-apart electrodes inlaid in a road surface, said measurement signal being a low-voltage, low frequency alternating voltage biased at ground potential;

    determining the ratio of current flowing between said pair of electrodes to voltage appearing across said pair of electrodes to thereby determine the conductivity of a covering on the road surface; and

    measuring the polarization between said pair of electrodes to determine the thickness of said covering.

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