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May 17, 2011

Comments

John Dunn

An update:

The LED traffic lights at the Telephonics driveway were at the time made as hexagonally arranged arrays of clear lensed LEDs. I drove by there more recently and it looks like the lights are now use light diffusers to spread the viewing angle. I don't know if the light sources themselves are still LEDs or if they've been reverted to incandescent lamps, but at least the viewing angle problem seems to have been addressed.

The ice accumulation issue is still with us, however. Please see:

http://www.universalhub.com/2011/city-seeks-help-motorists-identify-ice-encrusted-t

Cor van de Water

Hi John,
None of the problems you encountered were due to the LED technology, only due to to bad applications of LEDs.
BTW, a single bad LED does not turn a light off, it will only
render a few of the dots dark but the entire light (normally more than hundred LEDs) continues to operate normally.
What you saw was likely the driving electronics of the light,
or the wiring had gone out. That had nothing to do with the LED light and in fact, LEDs will operate longer on a certain battery if power is lost and a LED light will gracefully degrade with failing LEDs as I described, while the incandescent light will fail completely when the filament goes out, so it is the opposite of what you complain about.
Forgetting to use a solution to remove snow is also not a problem of the LED light itself, there are many ways to get rid of snow, there is no difference in getting snow on your car lights or on your windscreen, so how come your windscreen is not blocked by snow? Of course burning it away with a heat source is one solution, so using an incandescent light is one of the possible solutions, not necessarily the best one.
Good solutions usually come about with either carefully considering all possible situations and rigid design, or they evolve from practical experience. It appears that the LED light mounting (a mechanical problem, not a LED problem) is of the latter type...

Anthony Lang

I've seen LED lights here in Florida (no snow problem here) that have gone out in groups of 4-6 LEDs leaving a gap in the light. A few days later, that same light is missing another couple of strings and the next week only about 2 or 3 strings of lights are lit.
Seems that this is a quality control issue as much as poor design.
LEDs have great potential. I have one here, an array, that puts out over 2000 lumens at about 21 Watts. Put 3 of these and their power supplies in each lamp and you're still energy efficient (one switches in when the other goes out) and very bright.

Robert E. Yablonski

Here in southern California a lot of the lights have multiple LED's out. This starts with a few and within a few days the segment (red or green or amber will be out). This is a very frequent occurrence.

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