LED Traffic Signal Monitoring, Maintenance, and Replacement Issues (2008) / Chapter Skim
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Appendix A - Agency LED Traffic Signals Survey
Appendix A - Agency LED Traffic Signals Survey
Pages 12-26
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From page 12... ...
Additionally, use of LED traffic signals is growing and will continue to grow due, in part, to the recent Department of Energy requirements on signal manufacturers. Therefore, more information is needed to enhance understanding of the maintenance issues faced by public agencies that own, operate, and maintain LED traffic signals.
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From page 13... ...
4 5% Total 75 100% 3. How many traffic signals does your jurisdiction operate and maintain?
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: High ambient temperature 6 8% Wet weather 7 10% Electrical storms 14 20% Compatibility of external hardware 3 4% Poor quality utility power 3 4% Faulty module 40 59% Do not know 23 34% Other, please specify (see Table A9) 10 14% TABLE A2 EXPERIENCE WITH LED TRAFFIC SIGNALS (All questions apply only to LED traffic signal installations)
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No warranty is required 7 10% 3 year warranty 5 7% 4 year warranty 0 0% 5 year warranty 52 73% 6 year warranty 4 6% More than 6 year warranty 3 4% Total 71 100% 14. Is your agency purchasing LED traffic signals that have light output indicators that identify when light output falls below the specified level?
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If your agency routinely conducts compliance testing on samples of newly purchased LED modules (either in-house or through a lab) , which of the following tests do you run for LED traffic signals (check all that apply)
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Where a maintenance program is based on scheduled replacement of LED modules, some may be faded below specification levels prior to replacement. What maximum percentage of LED modules faded below specification levels does your agency consider acceptable with a scheduled maintenance program?
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Routine, scheduled replacement 17 24% Complaint driven 25 35% Replace when recommended by vendor product life cycle 2 3% Module has an indicator that suggests it should be replaced 1 1% Based on in-service maintenance test results 2 3% No replacement program is established 25 35% Total 72 100% 25. If your agency replaces LED modules on a scheduled basis, what is the time period between replacements?
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If there were national standards for minimum light output, how would you recommend adhering to them? Field testing to a specified minimum light output value 10 14% Replacement schedules based on product service life from the vendor 19 26% Agency defined maintenance practices or procedures 43 60% Total 72 100% 28.
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32 All existing traffic signals are retrofitted with LED. Future traffic signals will be designed and constructed with LED.
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9. The LED traffic signal modules failed because of which of the following, other please specify: # Response 1 Moisture within LED unit 2 Manufacturer problem with green 3 Primarily yellow LEDs have had high failure rates 4 I believe some go out because of power surges 5 Aging 6 Power supplies, capacitors 7 Industry has yet to provide an explanation 8 Cold weather 9 Poor quality LED modules 10 Do not have traffic signal modules in the RM TABLE A9 QUESTION 9 COMMENTS
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# 1995 ITE Specification 1998 ITE Specification 2005 ITE Specification Other Specification (not ITE) 1 100% 2 100% 3 We called for screw in units for vehicle signals 4 80 – 100% 5 100% 0% Used Caltrans specs in interim on yellow intensity 6 50% 50% 7 80% 8 100% 9 100% Had to meet ITE or Caltrans specification 10 100% 11 5% 95% 12 25% 50% 25% 13 0% 85% 15% 14 FDOT approved products lists 15 100% with additional Toronto requirements 16 100% 17 3% 95% 2% 18 0% 75% 25% 0% 19 30% 20% 20 100% 21 25% 75% 22 Don't know Don't know Don't know 23 25% 60% Caltrans 24 ?
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12. If your agency does not use an ITE LED specification, how does your specification differ, other please specify: # Response 1 Will use the ITE specification when we replace 2 3 6 year warranty 4 N/A 5 FDOT does certification & testing of vendor 6 N/A 7 N/A 8 I don't believe it differs -- we just want the mfr.
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Does your agency use a specification other than the ITE LED specification for minimum light output to determine replacement or failure? # Response 1 FDOT specification 2 Per Caltrans specifications 3 Caltrans specification 4 1998 ITE spec with expanded viewing angles TABLE A13 QUESTION 21 COMMENTS
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2 Kansas DOT purchases, installs, and then turns over all traffic signal operations & maintenance to the local jurisdiction or authority. 3 We have incorporated ITE LED specifications and have been pleased with the results.
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We may have problems with smaller cities replacing the LEDs when they fail after the 7 year warranty because of added expense. 22 While market competition is increasing resulting in lower costs, the evolving specs and general lack of knowledge regarding LED technologies and photometric measurement have slowed the establishment of maintenance practices for these items.
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