The use of multi-conductor cable for a traffic control induction loop can extend loop life and reduce maintenance. Two years ago, traffic engineering electricians with the City of Madison, Wisconsin, developed a method for installing the wire. The electricians have found the cable performance excellent and no installations have failed. The problem with single-conductor wires is that they become exposed from pavement surface wear or they break from pavement movement and sealant failure. Shifts in concrete pavement or heaves in bituminous pavement can cause damage to the loop. Exposed wires rapidly deteriorate due to snow removal equipment and other vehicular traffic. A demaged loop can quit working altogether or, worse yet, fail intermittently, which makes it difficult for electricians to determine exactly what repairs are needed. To alleviate the problem, Madison traffic engineering staff experimented with multi-conductor cable on the premise that such a cable, particularly if it had thick and durable insulation, would stay in sawcuts better. After testing various cable assemblies, the electricians found 14/3G UF most suitable. The mass of cable allowed it to stay in the cuts better and the more continuous nature of the assembly created better adhesion of the sealant. In other words, the cable is one unit in the sawcut, rather than several; therefore, overall contact between the sealant and the insulation is better. Several benefits were noted after this method was implemented in Madison. Installation in new asphalt pavement takes less time than the standard practice of ussing multiple rounds of one wire for the loop. The need for subsequent maintenance is reduced because the cable loop is more durable thaan the single-wire loop. And, the cable costs about half as much as the wire. So in an installation that typically requires three rounds of single wire, a wire cost savings of more than 80 percent can be obtained by using the cable. Overall, the use of cable instead of wire reduces labor and materials costs; and, most importantly, improves the reliability of signal service. (Author) improves the reliability of signal service. (Author)

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  • Corporate Authors:

    International Municipal Signal Association

    P.O. Box 8249
    Fort Worth, TX  United States  76112
  • Authors:
    • Telvick, R A
  • Publication Date: 1985-6

Media Info

  • Features: Photos;
  • Pagination: p. 12-13
  • Serial:

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Filing Info

  • Accession Number: 00396706
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 25 2004 2:37AM