FOG WARNING SYSTEM TO BE INSTALLED ON VIRGINIA'S HIGHWAY SYSTEM AT CRITICAL LOCATIONS

THE FIRST FOG WARNING EQUIPMENT ON VIRGINIA'S STATE HIGHWAY SYSTEM WILL BE INSTALLED AT TWO LOCATIONS ON INTERSTATE 64 IN 1971. THE DETECTOR ON THE SENSING DEVICE, WHICH WAS DESIGNED IN GERMANY, CONSISTS BASICALLY OF A LAMP AND A LIGHT-SENSITIVE TUBE WITH SCREENS BETWEEN THEM. FOG PARTICLES IN THE ATMOSPHERE SCATTER TOWARD THE PHOTOCELL SOME OF THE LIGHT THAT PASSES UNDER THE SCREENS THAT PREVENT A DIRECT LIGHT-TO-TUBE ROUTE. THE ELIZABETH RIVER BRIDGE INSTALLATION INVOLVES BOTH FOG AND ICE WARNINGS. TWO AIR AND MOISTURE SENSORS ARE USED FOR THE ICE DETECTOR. ONE OF THE TWO IS HEATED TO RETAIN UNFROZEN MOISTURE, THROUGH WHICH A CURRENT IS CONDUCTED. WHEN THE SECOND SENSOR FREEZES, THE CURRENT IS CUT OFF, AND THIS ACTIVATES THE MESSAGE TO THE ICE AND SPEED SIGNS. THE SPEED LIMIT SIGN CAN BE TURNED ON MANUALLY ALSO, AND THEREFORE CAN BE USED WITH EITHER THE ICE OR FOG WARNINGS, OR WITH BOTH. THE ELIZABETH RIVER BRIDGE INSTALLATION WILL BE MADE AT A COST OF $68,735. /AH/

  • Supplemental Notes:
    • Vol 50, No 4, P 15
  • Publication Date: 1971-10

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Filing Info

  • Accession Number: 00226236
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 2 1972 12:00AM