EVALUATION AND IMPROVEMENT OF INDUCTIVE LOOP TRAFFIC DETECTORS

摘要: It was determined in 1980 that approximately a quarter of New York State's 15,000 inductive loop detectors, used to control traffic signals, were out order at any given time and maintenance-free for an average only 2 years. A study made find the major causes failures how reduce them. Installation methods elsewhere investigated, hundreds failed loops studied failure types causes. Data suggested mainly caused by improper installation, inadequate sealants, or wire failure. Encased (regular signal protected continuous smooth-bore polyethylene tubing), which provided greater freedom movement areas pavement distress, being evaluated other states. Also, instead diagonal cuts corners loop, it decided cut 90-degree angles then chisel core them, thus saving sawing equipment wear also having negligible impact on itself. Another cause is damaged broken because its floating surface sealed slot, can be avoided with simple hold-down device. Other recommendations included saws horsepower, complete pressurized washing drying saw slot enhance sealant bond. Laboratory tests developed evaluate sealants before purchase assure those would provide strength, longevity, water resistance, good bond pavement, flexibility, encapsulation, ease installation. York's new materials appear best currently available, program has been established continued evaluation these detector systems. special training video tape now available covers procedures.