In response to increased competition and acceptance of alternative vehicle detection technologies, inductive loop traffic sensors have become `smarter'. This article discusses some of their recent enhancements, ranging from better basic design to improved roadside controllers. Loop detector technology is now both reliable and accurate. For example, Nortech has developed its accurate, fast, reliable TD624ES and TD624NS highway application detectors in the Eurocard and NEMA formats, respectively, for Intelligent Transport System (ITS) applications. In a typical ITS CITRAC system, several kerbside or intelligent vehicle loop detector racks would feed into a roadside processing station, in turn linked to a central traffic control computer. Each detector has one of Nortech's serial communication cards. With remote execution and ability to download, this ITS system can be fine-tuned to ensure optimal usage. The system can request diagnostic data from a detector site, then determine errors or failed loop sensors. Even a detector itself can conduct a self-diagnostic test. Modular system design plays an important part in developing the Nortech ITS system.
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