LED Traffic Lights - Luxeons?

Here's a quote from one of Lumiled's datasheets (AB25 Luxeon Reliability)

"Since the Luxeon High-Power Light Source was introduced
in 1998, it has been used in over 1 million traffic signals,
each traffic signal using 12 to 18 Luxeon emitters, which
have been installed in traffic intersections around the world.
These traffic signal heads are operating continuously 24
hours a day, seven days a week...."

Around here many LED traffic lights are popping up all over the place. So are there really places that are using traffic lights made with Luxeons? I thought they were all just simliar to these. The ones around here don't seem like they are Luxeon based but then again I never really paid attentioned to them.

After all I have seen some Luxeon assys. that were said to be once part of traffic light sold on e-bay. There are some up for auction right now, here & here.

My Father is a Civil Engineer in Indiana, and does the CADing and recomendation stuff. He regularly uses the LED cluster for the red and green (amber LED not approved in Indiana), but he has never heard of the Luxeon ones. I have been in field service traveling the country for the past 5 years and, to my knowledge, never seen a non-LED-matrix traffic siginal. I would guess however that if the LEDs on Ebay were part of a traffic siginal, it would probably be from a narrow angle device, ie. visible to only 1 lane.
Jeff

my town has upgraded to led traffic lights for cost reasons and such. i am not sure if they are luxeons but i know that they're bright

I've never seen a Luxeon based unit around here. All the locals have been using multi-5MM arrays. We're using various mfrs of them here, but all smaller, tho I think one style was the chip-on-board version. They also have a rather high failure rate ,IMHO. A lot of them have crude reactance supplys that fail. And I've seen more than a few that don't compensate for inrush. (Bright flash when initially powered, then settle..)

My buddy was collecting dead ones and troubleshooting them for fun and profit. Very variable quality..

Yours, drs the crazed and opinionated.. With an Econolite 820 (?) traffic controller in my truck..

Looks like those on ebay are from "walk/don't walk" displays, not the traffic lights themselves...

I suspect at least some come from GELcore.

One things I've noticed, is when there is snow on the LED ones, then it's hard to see them in the daytime. Incandecnts would melt the snow, but alas LED can't.

EDIT: Two more things: Our LED lights here aren't diffused or anything, you see the bare LED's and it's quite painfull. I've seen some models online that aren't like that and should be much better, and probably glow more evenly.
Secondly: seems as all of the traffic lights are made with blue-green LED's. They aren't pure green as a pure green luxeon is. They aren't the blueish true <font color="cyan">cyan</font> though. More like an inbetween or a bad greenish-cyan luxeon. I suspect this is due to color blind people and not confusing them with a higher green wavelength?
I even noticed online the manufacturers list the wavelength as 505nm which falls into the wavelenghts for cyan from the lumileds datasheets.
I wonder if those luxeon traffic lights then are Green, or Cyan? If they are Green, then I wonder if they are special bin codes to be on the blue-er side?

LED's save a lot of money in red and green traffic lights because they use so much less power than an incandescent lamp covered by a red or green lens that throws away most of the output. The dollar savings are lower for the yellow light, since the yellow light in a traffic signal is on for a much lower percentage of the time than the red and green lights.

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IsaacHayes said:
Secondly: seems as all of the traffic lights are made with blue-green LED's. They aren't pure green as a pure green luxeon is. They aren't the blueish true <font color="cyan">cyan</font> though. More like an inbetween or a bad greenish-cyan luxeon. I suspect this is due to color blind people and not confusing them with a higher green wavelength?

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I believe that's true. I remember reading once that green traffic lights are slightly bluish to help red-green color blind people more easily distinguish them from red lights. However, my red-green color blind father-in-law usually just relies on the position of the light (green being either on bottom or right of the signal) instead of the relative color.

I was near a green LED traffic light that was mounted pretty low, once, and it appeared to have a mix of green and blue LEDs in the array. I suspect that the blue ones were added because the green ones weren't blue enough.

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paulr said:
LED's save a lot of money in red and green traffic lights because they use so much less power than an incandescent lamp covered by a red or green lens that throws away most of the output. The dollar savings are lower for the yellow light, since the yellow light in a traffic signal is on for a much lower percentage of the time than the red and green lights.

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While this may be true, the real cost savings is in labor, LEDs last a LOT longer than incandesant. I'll bet they are much more expesive to buy than incan. too.

Pretty much 98% of our city is converted the reds/greens. We now have a few lights that have the Yellow/amber LED's in them. Not only are these lights on less than Red/Green, but they probably use a lower wattage bulb, as the color filter yellow, doesn't block as much light from the bulb as say a green one would. Mainly replacing these would be just for long life benefits, and consistancy.
I too have noticed some that seemed to be a mix of blue and green LEDs. But mainly they are all green.

Now I wonder about the color of the luxeon traffic lights. Are they high color binned cyans (4-6), or low color binned greens (123)?

I have several of their units. The green is a mixture of greens that are in a range of colors. This is done because the exact color of green approved by the DOT cannot be re-created via one LED. I will be in their lab next week on an unrelated project, but I can prod them for some info.

The two biggest reasons these are being used are power consumption and maintenance. You would think that the cost savings in energy consumption is the biggest reason, but it's maintenance. LED signal heads have a much much lower mean failure rate. Whenever a signal head goes out, it costs some bucks to replace. First is personnel, another large expense is Maintenance and Protection of Traffic (MPT). This usually involves a police officer, equipment, and sometimes an attenuation barrier truck.

A lot of the newer signal heads use the fresnel lens now so the signal head has a similar output as a conventional head. Most of the amber fixtures also need the filter to help correct the color.

All the conventional signal heads use the same wattage bulbs. They are an odd wattage bulb (I've got 'em around here somewhere) that is highly resistant to vibration, transient voltage, and surges.

EDIT: I should say that there are two different wattage bulbs, but they are not mixed in a head unless there is an exclusive phase (signal phase, not power phase) for a turn.

Around here, and we are talking Counties (Harris and Brazoria), Cities (Houston, Friendswood, Pearland and many others) etc. There are a LOT of intersections with LED traffic signals.

The Greens are almost painful at night! And there are WAY more than 12-15 LEDs in each lamp!

I think I heard of two major cost savings. Labor, and Electricity costs!

Anyhow, I LIKE em!

Ya I wish they had the fresnel, or faceted lenses on our LED lights here. They are painfull at night since they are so directional! The REDS are painfull here too!!

Beretta, I saw some bulbs on eBay that go into traffic, lights, said they were 120watts. Seems a little low to me but /ubbthreads/images/graemlins/icon3.gif They were marked as long life.
Oh, and why do they make Blue traffic light circles? Might ask them that when your there. I wonder what that would be used for??!?

Blue, cool. I hadn't seen those yet. Their info sheet says, "Ideal for applications requiring an additional
signal color".

My guess is for private applications or something to do with hospitals, but I will certainly ask.

I saw some weird-azz traffic light near where i work. It seems like an incandescent or whatever with a huge protruding magnifying lens on it, giving different intensities at different angles. The light is uniform and smooth tho when you get a direct view.

Speaking of Luxeons, is there any technical reason why 2 watt and 4 watt luxeons are not common?

All we see is odd numbered watt Luxeon. Can someone please explain why?

Thanks in advance.

I work on signals as part of my duties, tho not so much as years past. The traffic lamps are 67-69 watts, 130V rated and 8000 hour life. The larger one is 116W 130V 8000 hours. The 'funny' ones with the smooth look dead on are the 3M 'focussed' or directional ones, which use a 2 pin PAr like lamp about 120W. These are set up to be tightly directional, for signals that they don't want seen from other lanes. The energy savings is a biggie, but Beretta pegs the real savings, tho, is that you have to change those standard bulbs at best, every two years, and usually only a year or so.. The labor and equipment costs for the job itself and the public safety aspects is $$$. If the LEDS hold up for min 5 years and hopefully 10, now we're talking.

The other big advantage now is that more signals are being UPSed. A UPS that'll keep up an all LED signal is a lot smaller/more runtime than the incandesent. An average signal eats about 1200-2200 watts, depending on heads, peds and turn lanes. (Figure maybe 20 lamps at 116w each on at any given moment?) LEDs can knock that back to 250W or so..

Enjoy, yours, DRS the crazed..

(*&#@Q$(*&$ I HATE IE. LOST MY POST.
NightShift: what DRS said. It's to make it viewable only dead on.

DRS: I've seen 120/130/150 watt bulbs on ebay. So it varies I guess. Another stability benefit of LEDS is turning them on/off quickly doens't reduce their life. The yellow incandecent bulbs in the yellow part of the lights may not be on long, but they also don't get got enough to re-deposit the tungsten back on the filimanet and the rapid heating cooling also stresses it...

One thing I wonder if they are doing on newer LED modules is to create a fade-in/fade-out feature. The abrupt fast turn on of a split second is weird/confusing of LED lights especailly when they flash at night. A capictor in series would give fade in, and for fade out, one in parallel...