LED Traffic Signal Monitoring, Maintenance, and Replacement Issues (2008) / Chapter Skim
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Pages 3-7
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From page 4... ...
The VTCSH Part 2 was intended to provide interim specifications while further human factors and photometric tests were completed on LED traffic signal modules. Studies on the effects of luminous intensity, chromatic variation, and degradation of light output needed to be fully understood before the ITE specification could be updated.
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From page 5... ...
This creates an inconsistency in the expectation of two devices that should operate in harmony. A load switch is a solid state device, containing triacs, which is designed to use the traffic signal controller's low voltage DC outputs to switch on high voltage AC outputs to the signal heads.
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From page 6... ...
• Many agencies are now approaching the life span of their initial installations. • Most use a 5-year warranty, but scheduled replacement tends to be on a greater than 6-year cycle; therefore, there is a growing likelihood of old LED signal modules in the field with light output that is below specification.
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From page 7... ...
The manufacturer has stopped making this LED due to Energy Star requirements for wattage. Louisiana DOTD is concerned that the lack of output monitoring can lead to an unsafe condition.
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