TRIS Online Record

Printable View

Title	STAYING IN THE LOOP: THE SEARCH FOR IMPROVED RELIABILITY OF TRAFFIC SENSING SYSTEMS THROUGH SMART TEST INSTRUMENTS
Accession No	00757735
Authors	GIBSON, D; Mills, MKP; Rekenthaler, D
Journal Title	Public Roads Vol. 62 No. 2
Corp. Authors / Publisher	Federal Highway Administration ; Federal Highway Administration
Publication Date	19980900
Description	p. 47-51; Figures(1); Photos(4); References(1); Tables(2)
Languages	English
Abstract	If the sensor that is part of a traffic signal control system, known as an inductive loop (IL) detector, does not work correctly, the traffic signal controller cannot optimally control traffic. Therefore, the performance of the loop detector system, which includes the wire in the roadway, the sensor electronics in the cabinet, and the lead-in wire connecting the two, is critical to minimizing traffic delays, traffic stops, and air pollution. This article explains why loops fail, why an IL loop test instrument is needed to test them, and how the Federal Highway Administration developed the inductive loop tester (ILT). The first effort was an experimental concept design called ILT I. Because ILT I was never actually commercialized, ILT II was the first true product produced under the ILT research. It was field tested in many cities under a wide range of conditions. These tests uncovered a variety of limitations in using the device. This feedback provided the basis for the development of ILT III, which included a megger to measure the condition of the insulation of the loop and lead-in cables. ILT III, in its current form, still does not meet all the needs of a complete IL diagnostic system. An expert system, a system that could guide the technician in selecting which advanced diagnostics tests to run, is needed.
TRT Terms	Control systems ; Detectors ; Diagnostic tests ; Equipment tests ; Expert systems ; Failure ; Field tests ; Loop detectors ; Technological innovations ; Traffic signal controllers
Identifier Terms	U.S. Federal Highway Administration
Other Terms	Diagnostic equipment; Federal highway administration; Inductive loop testers; Inductive loops; Test equipment
Subject Areas	H54 OPERATIONS AND TRAFFIC CONTROL; I73 Traffic Control
Availability	Government Printing Office Find a library where document is available Order Document: http://worldcat.org/oclc/1586080
URLs	Document: http://www.tfhrc.gov/pubrds/septoct98/loop.htm
TRIS Files	HRIS
Database	TRIS Online