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28 SURVEY DESCRIPTION The Institute of Transportation Engineers (ITE) is seeking to better understand maintenance issues associated with light emitting diode (LED) traffic signals. LED traffic signals represent a fundamental shift in technology from incandescent traf- fic signals and have unique characteristics that must be taken into account in maintenance practices. 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. ITE requests your assistance by completing the following short survey. All individual information and responses will remain confidential. RESULTS OVERVIEW The following tables summarize the responses received. APPENDIX B Vendor LED Traffic Signals Survey
29 3. How long has your company been supplying LED traffic signals? Less than 6 months 0 0% Between 6 months and 1 year 0 0% Between 1 and 5 years 0 0% More than 5 years 6 100% Total 6 100% 4. If you are aware of instances of total burn-outs (black face) of whole LED traffic signal modules within the warranty period or within 60 months of installation (if there is no warranty period), what percentage of the total LED traffic signal modules failed? None 0 0% Less than 1% 5 83% Between 1 and 5% 1 17% Between 5 and 10% 0 0% More than 10% 0 0% Total 6 100% 5. The LED traffic signal modules failed because of which of the following (check all that apply): High ambient temperature 1 16% Wet weather 2 33% Electrical storms 4 66% Compatibility of external hardware 0 0% Poor quality utility power 1 16% Faulty module 4 66% Do not know 1 16% Other, please specify (see Table B7) 2 33% 6. When considering the failed LED traffic signal modules above, what was the predominant root cause(s) of the malfunction (check all that apply)? Design inadequacy 2 33% Poor product quality 3 50% Act of god 2 33% Poor power source 1 16% Improper application 1 16% Undetermined 1 16% Other, please specify (see Table B8) 2 33% TABLE B2 EXPERIENCE WITH LED TRAFFIC SIGNALS (All questions apply only to LED traffic signal installations) 2. The primary role of my company is: LED manufacturer/vendor 1 17% Traffic signal manufacturer/vendor 5 83% Total 6 100% TABLE B1 BACKGROUND
30 7. Of the LED traffic signal procurements you are familiar with, how many used the 1995 or 1998 ITE LED circular ball specification for purchasing LED traffic signals? All 0 0% More than 75% 1 17% Between 50 and 75% 3 50% Between 25 and 50% 0 0% Less than 25% 1 17% None 1 17% Total 6 100% 8. At this time, how many LED traffic signal procurements are using the 2005 ITE LED circular ball specification? All 0 0% More than 75% 3 50% Between 50 and 75% 0 0% Between 25 and 50% 0 0% Less than 25% 3 50% None 0 0% Total 6 100% 9. For procurements that do not use the ITE LED specification, how do these specifications differ (check all that apply)? Extended viewing angles 6 100% Higher light output values for red 1 16% Higher light output values for green 1 16% Higher light output values for yellow 2 33% Lower light output values for red 0 0% Lower light output values for green 1 16% Lower light output values for yellow 2 33% Other, please specify (see Table B9) 2 33% 10. Of the LED traffic signal procurements that include a warranty period, what is the warranty time period 3 year warranty 0 0% 4 year warranty 0 0% 5 year warranty 6 100% 6 year warranty 0 0% More than 6 year warranty 0 0% Total 6 100% 11. Of the LED traffic signal procurements you are familiar with, how many specify light output indicators that identify when output fails below the specified level? All 0 0% More than 75% 0 0% Between 50 and 75% 0 0% Between 25 and 50% 1 17% Less than 25% 5 83% None 0 0% Total 6 100% TABLE B3 PROCUREMENTS FOR LED TRAFFIC SIGNALS
31 12. When you do product testing, which of the following tests do you run for LED traffic signals (check all that apply)? Photometric testing 3 75% Chromaticity 3 75% Drive current 3 75% Power factor/total harmonic distortion 3 75% Transient protection 3 75% Compatibility with other signal equipment (MMU, load switches, etc.) 2 50% 13. In your experience, what types of practices or procedures do agencies have for ongoing sample testing and/or replacement of LED traffic signals? Most have a documented practice or procedure 1 17% Most have an informal practice or procedure 2 33% Most do not have a specific practice or procedure 2 33% Do not know 1 17% Total 6 100% 14. In addressing the issue of minimum light output, which do you think is the preferred approach? Mandated national standard for minimum light output 2 33% National guidelines on minimum light output 4 67% Minimum light output defined by engineering judgment as determined by the agency 0 0% Total 6 100% 15. If there were national standards for minimum light output, how would you recommend agencies adhering to them? Field testing to a specified minimum light output value 0 0% Replacement schedules based on product service life from the vendor 2 33% Agency defined maintenance practices or procedures 4 67% Total 6 100% TABLE B4 APPROVAL OF LED TRAFFIC SIGNALS FOR USE TABLE B5 ONGOING MAINTENANCE POLICIES AND PROCEDURES TABLE B6 POLICY ISSUES
32 5. The LED traffic signal modules failed because of which of the following, other please specify: # Response 1 Improper handling during storage and installation 2 Various 6. When considering the failed LED traffic signal modules above, what was the predominant root cause(s) of the malfunction, other please specify: # Response 1 Modules often discarded without failure analysis 2 LED electrical characteristicsâvariability 9. For procurements that do not use the ITE LED specification, how do these specifications differ, other please specify: # Response 1 Custom pedestrian signal requirements 2 Light degradation warning device TABLE B7 QUESTION 5 COMMENTS TABLE B8 QUESTION 6 COMMENTS TABLE B9 QUESTION 9 COMMENTS
