Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 12
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.
OCR for page 13
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%
OCR for page 14
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)
OCR for page 15
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%
OCR for page 16
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
OCR for page 17
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)
OCR for page 18
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%
OCR for page 19
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
OCR for page 20
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)
OCR for page 21
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
OCR for page 22
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)
OCR for page 23
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
OCR for page 24
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
OCR for page 25
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)
OCR for page 26
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.
