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Citation |
Lee CE, Huang L. Transp. Res. Rec. 1993; 1410: 89. |
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Copyright |
(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing) |
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DOI |
unavailable |
PMID |
unavailable |
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Abstract |
The typical high-occupancy vehicle (HOV) facility in Houston, Texas, is a single, 22-ft-wide, reverse-flow lane situated in a freeway median and separated from the adjacent freeway main lanes on each side by a concrete median barrier. Arrays of inductance-loop vehicle detectors in the pavement, along with remotely controlled television cameras on high poles, are used routinely for surveillance and traffic monitoring activities. As part of a research study designed to identify and evaluate traffic sensors that feasibly can be used in lieu of the loop detectors, especially on bridges, the Center for Transportation Research, the University of Texas at Austin, designed, installed, and evaluated a traffic data acquisition (TDA) system that features a pair of infrared light beam sensors and a microprocessor. Evaluation of the system showed errorless detection of the direction of travel--critical information for managing a reverse-flow HOV lane--and perfect counting of vehicles, even during a period of heavy rainfall. The TDA system also produces speed, headway, and vehicle-length data. Digital data to and from the system can be transmitted over conventional communication links. The sensors have been operational for the past 13 months without adjustment or maintenance. The TDA system potentially has traffic-monitoring applications other than on the Houston HOV lanes. Language: en |