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13 APPENDIX A Agency LED Traffic Signals Survey 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 traffic 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 manu- facturers. 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.
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14 TABLE A1 BACKGROUND 2. Please check one: City/Municipality 34 45% County 17 23% State/Province 20 27% Other, please specify 4 5% (see Table A7) Total 75 100% 3. How many traffic signals does your jurisdiction operate and maintain? Less than 50 11 15% 50 150 signals 16 22% 151 500 signals 20 27% 501 1000 signals 10 14% More than 1000 signals 17 23% Total 74 100% 4. What is your jurisdiction's population? Less than 50,000 9 12% 50,000 250,000 20 27% 250,000 500,000 9 12% 500,000 1,000,000 10 14% More than 1 million 25 34% Total 73 100% 5. What percentage of your individual traffic signal indicators (including pedestrian signals) use LED modules? Less than 10% 6 8% Between 10 and 30% 16 22% Between 30 and 50% 8 11% Between 50 and 80% 15 20% Between 80 and 99% 18 24% 100% 11 15% Total 74 100% 6. Does your agency have plans for full conversion to LED traffic signals (See Table A8 for comments) Yes 60 85% No 11 15% Total 71 100%
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15 TABLE A2 EXPERIENCE WITH LED TRAFFIC SIGNALS (All questions apply only to LED traffic signal installations) 7. How long has your agency been using LED traffic signals? Do not use LED traffic 1 1% signals Less than 1 year 2 3% Between 1 year and 5 31 42% years More than 5 years 40 54% Total 74 100% 8. If your agency experienced 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 9 12% Less than 1% 24 33% Between 1 and 5% 31 43% Between 5 and 10% 7 10% More than 10% 1 1% Total 72 100% 9. The LED traffic signal modules failed because of which of the following (check all that apply): High ambient 6 8% temperature Wet weather 7 10% Electrical storms 14 20% Compatibility of external 3 4% hardware Poor quality utility 3 4% power Faulty module 40 59% Do not know 23 34% Other, please specify 10 14% (see Table A9)
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16 TABLE A3 PURCHASING LED TRAFFIC SIGNALS 11. Now that ITE has released the 2005 LED circular ball specification, does your agency plan to use it? Yes 61 82% No 13 18% Total 74 100% 12. If your agency does not use an ITE LED specification, how does your specification differ (check all that apply)? Extended viewing angles 6 21% Higher light output 1 3% values for red Higher light output 2 7% values for green Higher light output 1 3% values for yellow Lower light output 1 3% values for red Lower light output 2 7% values for green Lower light output 2 7% values for yellow Other, please specify 18 64% (see Table A11) 13. What warranty time period does your agency require for LED traffic signals? 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 3 4% warranty 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? Yes 4 6% No 67 94% Total 71 100%
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17 TABLE A4 APPROVAL OF LED TRAFFIC SIGNALS FOR USE 15. Does your agency rely on a Qualified Products List (QPL) when making a purchase of LED traffic signal modules? Yes, the QPL is maintained by my 31 42% agency No 24 33% Yes the QPL is maintained by this other 18 25% agency (see Table A12) Total 73 100% 16. Does your agency routinely conduct compliance testing on samples of newly purchased LED modules (either in-house or through a lab)? Yes 11 15% No 61 85% Total 72 100% 17. 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)? Photometric testing 5 10% Chromaticity 3 6% Drive current 4 8% Power factor/total 2 4% harmonic distortion Transient protection 2 4% Compatibility with other signal equipment (MMU, 6 12% load switches, etc.) We do not do 37 77% compliance testing
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18 TABLE A5 ONGOING MAINTENANCE POLICIES AND PROCEDURES 18. What type of practice or procedure does your agency use for ongoing sample testing and/or scheduled replacement of LED traffic signals? We have a documented 6 8% practice or procedure We have an informal 23 32% practice or procedure We do not have a specific practice or 44 60% procedure Total 73 100% 19. How is follow-up testing done? In the field only 35 88% In the lab only 2 5% In the field with follow- 3 8% up lab tests Total 40 100% 20. What follow-up tests are run on LED traffic signals (check all that apply)? Photometric testing 11 39% Chromaticity 2 7% Drive current 1 3% Power factor/total 1 3% harmonic distortion Transient protection 1 3% Compatibility with other signal equipment (MMU, 21 75% load switches, etc.) 21. Does your agency use a specification other than the ITE LED specification for minimum light output to determine replacement or failure? No, we use the ITE LED specification for 34 52% minimum light output No, we do not have a specification for minimum light output to 27 41% determine replacement/failure Yes, the specified minimum light output is 5 8% (see Table A13) Total 66 100% 22. In an LED module with some dark pixels, what triggers the decision to replace the module? Primarily, a percentage of the total LEDs on the 19 29% module that have failed Primarily, an alteration 8 12% of shape Combination of percentage and change 38 58% in shape Total 65 100% 23. 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? Less than 1% 2 5% 1% to 5% 16 39% 5% to 10% 14 34% 10% to 15% 4 10% Greater than 15% 5 12% Total 41 100% (continued on next page)
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19 TABLE A5 (continued) 24. What type of replacement approach does your agency use for LED traffic signals? Routine, scheduled 17 24% replacement Complaint driven 25 35% Replace when recommended by vendor 2 3% product life cycle Module has an indicator that suggests it should be 1 1% replaced Based on in-service 2 3% maintenance test results No replacement program 25 35% is established Total 72 100% 25. If your agency replaces LED modules on a scheduled basis, what is the time period between replacements? 3 years 0 0% 4 years 0 0% 5 years 11 38% 6 years 3 10% Greater than 6 years 15 52% Total 29 100%
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20 TABLE A6 POLICY ISSUES 26. In addressing the issue of minimum light output, which do you think is the preferred approach? Mandated national standard for minimum 16 22% light output National guidelines on 40 55% minimum light output Minimum light output defined by engineering 17 23% judgment as determined by the agency Total 73 100% 27. If there were national standards for minimum light output, how would you recommend adhering to them? Field testing to a specified minimum light 10 14% output value Replacement schedules based on product service 19 26% life from the vendor Agency defined maintenance practices or 43 60% procedures Total 72 100% 28. Does your agency have financing in place for ongoing monitoring and maintenance of LED traffic signals? Yes, we have adequate financing for monitoring 16 23% and maintenance Some financing for monitoring and 21 30% maintenance is available but is not adequate No, financing for monitoring and 34 48% maintenance has not been arranged Total 71 100% TABLE A7 QUESTION 2 COMMENTS 2. Please check one, other please specify. # Response 1 Consultant (Prior City of Jackson, MS) 2 Consultant 3 Consultant
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TABLE A8 QUESTION 6 COMMENTS 6. Does your agency have plans for full conversion to LED traffic signals? # Response 1 When funding is available. 2 Over the next 3 years. 3 5 to 10 years. All new installations will be LED. We've recently incorporated the New ITE LED 4 specifications for circular indications. 5 Now complete. We plan to use surplus 100% State maintenance funds. Under a letter of understanding municipalities or IDOT will carry out the retrofit and charge the 6 other agency its proportionate share. Retrofit would be in two phases, Phase 1: within 12 months and Phase 2: within 30 months. 7 As halogen bulbs expire. 8 PennDOT does not own or operate signals. Municipalities do. We are waiting for the approval of the yellow LED vehicle signal by ITE. After 9 that we will implement them and should be 100% LED. 10 2008 11 Over the next 5 years. 12 Over the next two years, final 1%. A few yellow and walks to do. 13 On-going as budgets allow. In 2007 we will have all LEDs. We are finishing the yellow balls so we can use 14 battery backup UPS at all intersections. 15 We upgrade to LED lights during our signals during routine PM Program Currently in year 3 of an 8 year program converting all except yellow. Yellow 16 will be replaced in years 9 through 16 (when the first LEDs are replaced). 17 We are in the 3rd year of 6 year plan to fully convert. We will be complete by the end of this year for locations we pay the electric bill. 18 Total of maintained locations is 45%ish. 19 By 2011 20 When there is one that deals with snow accumulation issues. Of the ~750 signals we maintain, ~250 are county owned. Our program deals only with these 250. We are half way through a 5 year program to convert these 21 locations. The Maryland State Highway Administration owns the remaining ~500 signals in the county. Their program at present calls for LEDs as part of new builds and major modifications but not conversion of existing. There are a couple of factors that will drive this change. Factor number one is the lack of availability/increased price for incandescent fixtures. Factor number two would be legislation to use LED modules only. Factor number three is a cost 22 benefit analysis between incandescent and LED--taking into account the difference in maintenance needs and maintenance issues (e.g., snow removal from the lenses in winter) 23 Within two years. 24 Everything but amber. 25 Already 100% LED. The only items left are pedestrian heads. They will be changed out as they wear 26 out or the intersection is upgraded for other reasons. 27 We should be completed by mid 2008. 28 Full conversion by 2008. 29 Implemented over 10 year period ending in 2015. 30 When the financial budget allows. 31 Already done. All existing traffic signals are retrofitted with LED. Future traffic signals will be 32 designed and constructed with LED. 33 3 years 34 We have a five year conversion plan for all of our 4300 traffic signals. 35 This year we should be complete. 36 Program completed in 2005. 37 New installations and all replacements will be LED; no set time period. 38 New installs and upgrades. 39 In the process. Due to LED module failures, the date is open; however, our intent was to be 40 within 5 years. 41 Currently on-going as funding permits. 42 2008 As locations are modernized with annual projects or in new installations. This 43 will take 10 years. All state-owned vehicular indications, except in one major municipality, have 44 been changed to LED. Will transition to pedestrian LED indications during future maintenance activities. (continued on next page)
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22 TABLE A8 (continued) 6. Does your agency have plans for full conversion to LED traffic signals? # Response 45 Yellow modules are not cost beneficial. Will only be replaced if required by law. 46 We initialized this process for full conversion in all new construction 2003. We do not plan on changing the yellow, they are too costly for the return, but we 47 do have all reds, greens, and peds. LED at this time. Also all new signals will be completely LEDs at time of install. 48 Not sure at present. 49 As funds permit. 50 Current schedule is for completion by June 2007. Within 2 years. Almost all vehicle indications have been converted. Remaining 51 conversions will be done through maintenance as incandescent bulbs fail. A contract will soon be let out to convert remaining pedestrian indications. Completed. Some signal heads that are incandescent will be replaced as part of 52 maintenance activities over the next 3 years. 53 100% by the end of 2007. 54 As funds come available each budget year. 55 Already completed As new signals are installed or replaced they go in as LED (began before this was 56 required). No plan to do blanket replacement. 57 We are in the process. TBD as part of maintenance and replacement program of existing heads. All new 58 traffic signals are equipped with LED lights. 59 Eventually over time 60 Project kickoff is October 6, 2006, with completion by December 31, 2006. 61 Over the next 5 years, depending on continued capital funding. TABLE A9 QUESTION 9 COMMENTS 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
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TABLE A10 QUESTION 10 COMMENTS 10. Approximately what percentage of your LED traffic signal modules was purchased using the following specifications? 1995 ITE 1998 ITE 2005 ITE Other Specification # Specification Specification Specification (not ITE) 1 100% 2 100% We called for screw in 3 units for vehicle signals 4 80 100% Used Caltrans specs in 5 100% 0% interim on yellow intensity 6 50% 50% 7 80% 8 100% 100% Had to meet ITE or 9 Caltrans specification 10 100% 11 5% 95% 12 25% 50% 25% 13 0% 85% 15% FDOT approved 14 products lists 100% with 15 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 ? ? ? ? We have always used a 25 specific mfr.'s spec 26 100% 27 90% 10% 28 100% 29 0% 0% 100% 30 95% 5% 31 80% 20% 32 100% 33 75% 25% 34 FDOT Our own City of LA 35 specification 36 35% 65% Did a big install in 2001 37 Tested (red & green), 2 years later yellow 38 65% 35% 39 50% 50% 1998 spec & 40 ALDOT spec 41 20% 80% 42 20% 80% Most have been We had our own spec 43 purchased with and referenced the 1998 this spec spec All red and green All arrow and yellow 44 circular circular 45 50% 50% Caltrans spec 46 100% 47 100% 48 90% 10% 49 0% 10% 90% (continued on next page)
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24 TABLE A10 (continued) 1995 ITE 1998 ITE 2005 ITE Other Specification # Specification Specification Specification (not ITE) 50 100% 51 99% None 100% of red LEDs 100% all LEDs 52 (2001-2003), all since 2005 other LEDs 2003+ 53 50% 50% 54 100% 55 80% 20% 56 70% 20% 10% 57 Caltrans specs 100% Caltrans & 58 customized LA County specs 59 10% 90% 60 Don't know Don't know Don't know 100% Caltrans 61 10% 85% 5% 62 100% 63 one purchased 64 0% ? ? 65 80% 66 30% 60% 10% 67 90% 10% 68 Internal spec 69 33% 10% 57% 70 100% 100% TABLE A11 QUESTION 12 COMMENTS 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. 9 Don't know what the ITE specs are. Update as B.O. 10 Heat tolerance 11 Caltrans for arrows and yellow circular 12 See #11 13 Still using Caltrans specs 14 Non-pixelized appearance required 15 However the Caltrans specs compare 16 We use ITE Standards 17 Do not use 18 Internal spec
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25 TABLE A12 QUESTION 15 COMMENTS 15. Does your agency rely on a Qualified Products List (QPL) when making a purchase of LED traffic signal modules; identify maintenance by other agency? # Response 1 ODOT 2 Caltrans QPL 3 FDOT 4 State, FDOT 5 Maryland State Highway Administration 6 Caltrans 7 GDOT 8 FDOT 9 Caltrans 10 We use NCDOT's QPL 11 FDOT 12 WSDOT 13 NCDOT TABLE A13 QUESTION 21 COMMENTS 21. 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
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26 TABLE A14 QUESTION 29 COMMENTS 29. Thank you for taking the time to complete the above survey on your jurisdiction's experiences with LED traffic signals. As a final item, please describe any other experiences (good or bad) that you have encountered that were not asked about in this survey. # Response 1 My power company refused to give a rate reduction to realize savings on LED installations. My information is about a year old since I left the City of Jackson in August 2005. 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. ITE specs provide minimum requirements to all vendors. 4 It is too bad that this is only for agencies. Many consultants have observations and thoughts with respect to LEDs that cannot be entered. This is especially true with respect to potential liability. This is a major consideration that is not included. 5 Different type of technologies (e.g., non-pixelated appearance LEDs) use less LEDs and when they start to go bad do not have half or part of the module not lighted. Aesthetically, they look better and in my opinion they operate better. 6 Good experiences--no more maintenance calls that one of the red, yellow, or green indications is out (dark). Now the crew can focus on other maintenance tasks. Signals don't go into flash as often because all bulbs of the same color on an approach out. Major cost savings in electric bills. Bad experiences--Convincing upper management when creating budgets why we need $80 instead of $2 to buy a light bulb. Determining how long to wait before changing an LED and how to make sure money is available when things need replacement. 7 Rely greatly on FDOT for specifications & certification of vendors. Have local signal maintenance group that notifies FDOT of common vendor problems &/or trends; whereby, FDOT will investigate. Our experience is generally as a relatively new LED user. However, we are pleased so far and like the LED signals. 8 You should adopt a two spec approach, the same as TS-1 and TS-2. 9 Dialight LED modules have many issues and are not recommended by Pinellas County from install to return for warranty. We recommend GELcore for all installs as they stand by the product and have never had problems with returns. Even when they discovered they had a bad batch of greens they delivered free replacements with no questions asked. 10 We use only Red and Green LEDs. There are currently no Yellow LEDs on the FDOT's QPL; this makes the purchase and use unbeneficial to our agency. There is also the added expense of using incandescent bulbs and the eventual cost of adding the yellows in the future. LED units are warranted through the manufacturer for 10 years which conflicts with the guidelines for life expectancy. The unit is warranted for 10 years but weather conditions in our area (FL) shortens the average life expectancy to 3-5. Also, the manufacturer's warranty period begins at the date of purchase, not installation date. This makes it difficult for agencies to store quantities of units in inventory. Warranties can expire while LED units remain in inventory (never being used in the field) if large quantities are purchased at one time. 11 I believe that you need to address the problems with snow accumulation and snow sticking in areas that this may happen. This will be a significant issue in the future. 12 We are in the third year of a four year plan to replace all red LEDs that were installed in 1998-1999. This phased-in approach establishes a routine replacement schedule to make sure that at least 80% of the red LEDs are under warranty in any given year. There is no scheduled replacement policy for green LEDs due to inadequate funding and higher replacement cost. Yellow incandescent signals still being used in 60% of our intersections are scheduled to be replaced by LEDs beginning this year. We do not plan to establish a time-based replacement schedule for these. Our history of LED usage since 1998 has shown that there are more complete failures of red LED modules than fading, and more partial LED failures in green modules than others. Also, some vendors have a higher failure rate than others, which creates a problem in purchasing based on low bid only. 13 Screw-in type green modules are really not working well in our county. We have had an extremely high failure rate with these units. 14 They have created substantial added work for staff and our maintenance contractor when they fail during the warranty period. You don't just toss them out like you would an incandescent bulb. (continued on next page)
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27 TABLE A14 (continued) # Response 15 Winter storms cause problems when wet snow builds up and sticks to the LED lenses. The heat generated by the LEDs is not enough to melt the snow and ice. 16 Our LEDs (red) have been in the field for 9 years and we are not experiencing a significant failure rate. We do not have a replacement program funded. We are doing replacement on a failured basis. 17 No real questions. I have noticed that some manufactures are a lot better than others. 18 If LED wattage keeps getting lower, MMU, conflict monitors will not operate properly. My understanding now is that the monitor is reading the transformer for the LED insert. 19 I feel on the warranty it should be 5 years replacement only. We have had some Pedestrian LED's that were repaired and they failed again within a couple of weeks of being reinstalled. We own a couple of LED testers and the district personnel run some random tests. At this time we don't have an official maintenance and testing procedure in place. 20 LEDs are necessary for UPS use. Undefined failures have caused us to discontinue use of a reputable manufacturer. 21 Almost all signals in the State are maintained by the City or County. The State provides tech and monitoring. 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. 23 After the failure rate of one type of LED exceeded the manufacturer's standard, he replaced 100% of the units. 24 Many agencies, including ours, do not yet have sufficient experience with LEDs. As time goes on, we will have better honed practices and policies in place. This is also likely true for other agencies. As an example, we have not yet experienced our first complete replacement of modules. 25 Sorry, I cannot provide more information for your survey since we do not have any traffic signals in our jurisdiction. 26 It would be nice if someone could come up with a reasonable method of checking LEDs in the field. Maybe something that could be done from the ground without disrupting traffic. 27 We like using the LEDs for the signals, especially the newer ones with a wider visual cone. 28 1. Yellows fade quickly it seems and do not have the brilliance of a light bulb and do not attract as much attention. (Plastic clouds over.) 2. Power Savings--It takes a long time to recoup cost. 3. LEDs tend to be "directional" and lose brilliance quickly if observer not in limited cone in front of signal; head timing is more critical; engineering design, more often than we prefer, places heads outside an optimal 20 degree cone of vision--this can be done with bulb not LED. 4. High winds in Reno area may etch plastic faces more quickly than LEDs are expected to last. Winds have blasted paint off cabinets at Mt. Rose highway.