Hi everyone!!! Como Estas Frijoles? - It's bean awhile since I have talked/typed with you guys
Got abducted by Aliens
[well, work Aliens - not outer space hombres] . Finally got a whole weekend off once again!

Got a question to throw at you about Traffic Signal Lamps in your area:
How many Signals have been upgraded in your area to use LEDs? These are just replacements for the A type lamps - similar to a CFL with intregal Ballast [includes a medium base screwshell].

Out here in So. California, many Cities / Counties have been in the process of replacing the typical Incandescent Lamps and Color Gels which are used for Red, Yellow and Green Signals, for LED arrays.

First one I had noticed was used at an Intersection that was under construction, where the Red signal was flashing over a period of 6 months [during the 5 freeway work].
The lamp's on-off characteristics were not the way an Incandescent Lamp would act [the gradual on, decayed off of an Incandescent Lamp] - that was what captured my attention. This was mid 1996.
Checked it out and sure enough this was an array of LEDs, possibly 10mm size.

Around mid 2K [July, 2000] I started to notice a few Intersections here and there with Red LED replacements.
By the beginning of 2001, nearly all Intersections were upgraded with Red LED arrays. Soon after, the first Green ones began popping up. Only have seen 3 Intersections with all 3 colors in LED arrays - nearly all at this time still use an Incandescent for the Yellow signal.

Anyone else noticed them??? - Curious if other States are planning to use them.

Did find some info on-line regarding this, problem is that it I cannot locate that bookmark for a link. I did print the stuff, so when it turns up I'll have the URL for anyone interested.

These LED pin arrays [or matrix if you prefer], are very cool! The Color is solid [typical of LEDs] - Green is GREEN!!!, instead of Blue-Green from the Incandescent/Gel. Yellow is more like an Orange, Red is Ruby-ish, instead of Pink-Red.
They surge into conduction [surge brightly, then stablize] when new. There's no visible Reluctance going on or off - just bam on/off!!!

Some Walk Signals have been changed from the Neon / Fluorescent tubes, to LED arays.
The "Walk" symbol uses White LEDs, whereas the "Don't Walk" symbol uses either Reds or Orange-Reds [like trichips or the tri-lead LEDS].

Like to hear [more like see] your comments and input.

TIA!!!

Scott SET

Hi Scott:

I haven't been in the States since I was working in central Nebraska in 1996, but I never saw LED signals there. Just before that I traveled pretty extensively around Ga, Ala, NC, SC and Fla, and again never saw any.

I've not seen any here in England yet either, but I was in France about two years ago, and noticed LED signals everywhere. As you said, the smart "snap" from one color to the next is what really gets the attention at first.

Many of the normal lights seem to have been converted, but it was hard to see the exact arrangement because they still appear to use a gel or lens of some kind.

Junctions with high suspended lights in France usually have a small repeater set mounted at eye-level for the driver at the front of the line. Just about all of these seem to be LEDs now, consisting of a dozen or so high-intensity LEDs arranged within a 2 to 3 in. dia. circle.

Up here in Canada, I have seen a lot of traf. lights using fiber-optics, which allows servicing or lamp changes from a safe place.I assume these are fairly common, but I haven't seen the LED's yet.

Haven't seen any traffic lights yet, but emergency vehicles are starting to use them for the warning lights. They can meet the NFPA warning light regulations with less strain on the battery and alternator. I've also seen some commerical truchs with led tail lights.
Don(resqcapt19)

I have installed a few of these units, all in the name of energy conservation. I changed all colors. Walk/don't walk couldn't be changed due to size.

I will get the specifi information Tuesday when I get back into my office.

One thing I have noticed. These units give off great light, but sometime the green makes it hard to see ahead of your vehicle.

PS. I only have two intersections that I have to maintain, other than these, there are 3 other sets, maintained by the State of Colorado highway dept., and these have been either changed (2 sets) or installed new (1 set) to use the new led type lamps.

I have a friend in Alamosa, Co. that won the state of Colorado contract to change all units in the state. Took about 3 months, in 1999.

Rick Miell

Hey Scott,
Been looking for you in the neighboring forum too for a while.
In Hesperia, CA next to Victorvill, in the High Desert,(On the way to Las Vegas from LA)
they have changed all of the signals to these LED's this summer. Really good light from these. Maybe it's also an attempt to get people to quite running so many red lights!
Nick

Thanks to everyone for the replies!

I'd like to address each reply with a "snip" of quoted text.

• pauluk

I've not seen any here in England yet either, but I was in France about two years ago, and noticed LED signals everywhere. As you said, the smart "snap" from one color to the next is what really gets the attention at first.

Exactly! They "snap" on or off so sharply, it's a real attention grabber. The colors are really solid also.

Many of the normal lights seem to have been converted, but it was hard to see the exact arrangement because they still appear to use a gel or lens of some kind.

The ones I have seen have only a clear acrylic cover [for waterproofing, diffusing?], but no colored gels. The Green arrays must be using clear LED cases because when the Green signal is off, it has an odd appearance. The Reds and Ambers [Yellows] must use colored cases as they are noticable when off.

Junctions with high suspended lights in France usually have a small repeater set mounted at eye-level for the driver at the front of the line. Just about all of these seem to be LEDs now, consisting of a dozen or so high-intensity LEDs arranged within a 2 to 3 in. dia. circle.

In California, there's a fixture type, similar to the repeater set, which is mounted on the pole at around 12 feet +/- above grade, which is supplimental to the fixture mounted on the Cantelevered extension. Some of them use smaller sized gels [about 1/2 the size of the overhead fixtures]. The LED replacements have around 30 LEDs, which look like 5.0 mm size.

• Mickky

Up here in Canada, I have seen a lot of traf. lights using fiber-optics, which allows servicing or lamp changes from a safe place.I assume these are fairly common, but I haven't seen the LED's yet.

I like that idea! Less risk of getting hit by passing cars, etc.
The driven light source might be from LED arrays, or from gelled Incandescents. I'm going to have to check this out more!!

• Don "resqcapt19

Haven't seen any traffic lights yet, but emergency vehicles are starting to use them for the warning lights. They can meet the NFPA warning light regulations with less strain on the battery and alternator. I've also seen some commerical truchs with led tail lights.
Don(resqcapt19)

I have seen more and more Trucks, Trailers - especially ones for flammable materials, such as Gasoline "1203"; and city busses (more than one bus - is that the correct spelling?? ] which are using LED arrays for tail lights plus marker lights. Haven't noticed if the Fire Trucks or Ambulances have changed over, so I'll look into this [I'll tailgate an Emergency Vehicle that's on call... just joking].

• Rick "rmiell"

I have installed a few of these units, all in the name of energy conservation. I changed all colors. Walk/don't walk couldn't be changed due to size.I will get the specific information Tuesday when I get back into my office.

Cool!!! We have someone with hands-on experience. If you could post some information here, that would be great!
If you have any information about them in non-hardcopy format [a data file on your computer at work], would it be possible for you to E-Mail it directly to me? I'm an info junky!

One thing I have noticed. These units give off great light, but sometime the green makes it hard to see ahead of your vehicle.

Heck ya!!! That is really some intense light output!

• Nick

Been looking for you in the neighboring forum too for a while.
In Hesperia, CA next to Victorvill, in the High Desert,(On the way to Las Vegas from LA) they have changed all of the signals to these LED's this summer. Really good light from these. Maybe it's also an attempt to get people to quite running so many red lights!
Nick

The Holt group was getting too hot from the flame wars, so I just decided to stay away. Besides, I feel more at home here at ECN!!!
Were all three colors, along with the Walk / Don't Walk signs changed to LEDs?
So, how hard is the heat wave hitting Hesperia?
My Wife went to Vegas this weekend, and on the way out there, got stuck in the traffic which builds up around Barstow. She called me and said that if you roll down the window, hot air blasted in like sticking your head in an HVAC duct! Man, that traffic sucks!

Well everyone, thank you very much for the input. If I come across some tech data, I'll post it to ECN - either in this area, or the reference section.

Scott SET

p.s. had to edit a smilee, which I made a typo on! Would have made your head spin decoding that one

SET



[This message has been edited by Scott35 (edited 08-19-2001).]

Scott,
All three colors were changed. I don't know about the walk/don't walk signs because I wasn't paying attention. I'm not at home right now (I'm down around your neck of the woods. San Clemente) but I'll check when I get back. It's been getting upwards of 105 Deg at home and yes the traffic through Barstow is terrible. I'm glad I don't have to deal with it.
Nick

Now a days, most of the signals are converted. The only ones not converted are owned by the township/borough, or Penndot forgot them. The Ped. Signals are also changed now. The LED upgrades replaces the lamp socket, reflector, and lense. The new module goes where the lense used to be. NYC, New Jersey, and PA are about 75-80% filled with LED traffic signals. Heres a bit more information: http://auto.howstuffworks.com/question178.htm

Ian A.


[This message has been edited by Theelectrikid (edited 10-01-2006).]

Mostly the red ones are replaced and then the green ones. The yellow ones aren't on for a very long time so they don't get replaced around here.
Evidently this will save energy.
~Peter

They installed the LED traffic lights here in Bergen County, NJ a year or two ago. In traffic lights the county owns. Town owned light are still light bulbs.

When listening to a distant AM radio station at night in the car, I hear some RFI from these LEDs when sitting at a red light or crossing the intersection.

Here in Washington State there has been a huge push to LED signal illumination, I believe for both operating and maintenance costs. The power savings, as spread over the state, are tremendous!

The sudden "snap" effect also caught my attention a few years ago and sure enough it was a LED head.

Another interesting item I spotted a couple of months ago was a red LED beacon mounted atop a "STOP" sign and it was solar/battery powered! Definitely needed where it was, too- the sight distance was terrible on approach to the intersection. I would like to see more of these in use.

Here in New York I see some have been converted. I have also seen a few incandescent reds that have been fitted with a strobe tube across it's face. These flash when the red is on. They do this at locations of poor visibility.

On the subject of LED's, Many high end cars are now using them for brake lights. I first started noticing them on some trucks like UPS and FEDEX.

You can always spot these by their instant on/off operation which is quite different than the familiar incandescent.

-Hal

 
Up here in Northwestern-Central East California, all the new development is pure LED, but the “blast-on” feature—that would surely decimate incandescents—seems to have gone out of style.

I understand that Hewlett-Packard {LEDs and everything else} and CalTrans {state road dept.} did a lot of development work up to several years ago. A ~100K town in the region carried an evening news report of getting a $150K rebate for signal retrofits from PG&E [“inspired”/ramrodded by the state energy commission, no doubt.]

For retrofits around here, changeouts are not wholesale in the heads—some green, some red, some both, fewer amber—but way too many obnoxious ADA “chirpers.”


[This message has been edited by Bjarney (edited 12-31-2004).]

Out here in Winnipeg MB it seems that they are being replaced as they burn out or if the signal pole gets hit the whole head gets replaced with LED. And of course new signal constructon gets the LED head as well.

The City of Winnipeg signals department also says that they can save money on pedestrian crossing heads by removing one of the two bulb ones on each pole and putting a single LED walk don't walk matrix head in. They try to do this when they have to relamp a head. From what I read in the newspaper the signals deptartment figures by doing this they won't have to buy new heads for about 8 or 9 years.

It looks a little funny as on one side of the street there is the normal two head pedestrian signal and the other side has the single walk don't walk head.

A few years the city of Chico,(CA)replaced the incandescent lamps w/ LEDs in their signals it took a bit of getting used to.

Noticed LED traffic signals appearing over here in Scotland over the last couple of years.

The thing that grabs my attention is the amount of signals that are unlit.

At a junction near my home all the greens were out for days. Not long after they were repaired some of the ambers were out.

I have noticed this at several sets of lights, some new installations and some converted.

Wishing everyone a happy new year.

simon.

My nearest traffic lights are about 10 miles away -- Only three sets in that town, and all still filament lamps. But in the city (Norwich) about 20 miles distant I've noticed that LEDs have started replacing regular bulbs the last couple of years, sometimes just one or two aspects. There's one particular set of lights on the ring road which is completely LED on every post, all regular aspects and the left/right-turn arrows.

Are they the annunciators which sound when the "WALK" sign is illuminated? We've had those on our "Pelican" crossings in Britain for quite a few years now, probably since about the 1980s. ("Pelican" crossings are lights placed mid-block to stop traffic specifically for pedestrians to cross.)

Almost all the new cars here for the last couple of years seem to use LEDs for the third, high-level, center brake light. The regular brake lights are still filament bulbs on most, although I've seen a few equipped with both LED brake and turn signals at the rear (all current cars made for Europe have independent amber turn signals, by the way).

I often find the green LED traffic lights excessively bright at night. I believe that the LEDs have been getting more efficient, but the power levels have not been cranked down to compensate. Also, of course, this same 'excessive' brightness is quite nice during the day.

-Jon

Interesting. I've read in our state DOT specifications about 150-watt amber flashing beacons having a dimmer function for what I believe is the same reason. I wonder if the spec will change when amber LEDs are used in this capacity...

If I counted all the intersections with traffic lights within a 10 mile radius of my home the number would not fit on this forum.

The majority of these have been retrofitted with green, yellow, red, LEDs.

I saw a Rescue truck with LED beacons on it for the first time recently, they where very effective.

LEDs are showing up in some car tail lights also. You can spot them right away for the reasons Scott has mentioned, the quick on & off times.

Here in Las Vegas I'd say that ~90% of the red are LED, 75% of green and only a small handfull (probably a test) of yellow are LED based. All new signals are LED based, except for yellow. Most of the pedestrian signals are now LED based. We also are seeing more of the pedestrian signals that give a flashing hand with a countdown timer to when the traffic signal will turn from green to yellow. We still have a huge problem on "The Strip" with pedestrians crossing against the signal on red lights. The only way we have found to combat this is to elevate the crosswalks above the road...

Mike, I guess the "jay walkers" must be New Yorkers. We've elevated that stupdity to an art.

I wish we'd get pedestrian bridges at some of our more dangerous crossings also.

As far as LEDs are concerened, I've seen retro-fit LED clusters that are meant to replace incandescent brake and turn lights in cars. It's a mass of LEDs in a conical holder that's attached to a conventional bulb-base.

I'm glad I'm not the only one who finds these new traffic lights excessively bright at night...then again, it seems like car headlights have also been getting brighter. That's even worse.

Happy New Year y'all!

Maybe we'll see lights being fitted with a photocell and dimmer circuit as standard once LEDs are firmly established?

LOL! Well, I'm in rural area, and British intersections tend not to have lights as often as U.S. ones anyway.

The local car accessory shop has them here, along with LED bulbs specifically for backup lights which incorporate a beeper.

"Yes, folks, you too can annoy everybody within a 100-yard radius by having an annoying beeper when reversing just like the buses!"




[This message has been edited by pauluk (edited 12-31-2004).]

 
Paul, I don’t know for sure if pedestrian-crossing chirpers are Americans-with-Disabilities-Act originated, but they seem to be for assisting the ‘vision-deprived’ in street crossing.

For those with way too much extra time, or need reading material during a tedious alien abduction... {HP’s new frou-frou name is Agilent} www.agilent.com/about/newsroom/features/gettoknow/030102electronics.pdf
Studies by the University of Michigan Transportation Institute show that LED center high mount brake lights yield a 170-200 millisecond advantage in braking response time in favorable lighting conditions and a 300 millisecond advantage in poor lighting conditions due to their conspicuous, fast turn-on time.

…and www.agilent.com/about/newsroom/presrel/2004/10may2004c.html
…and www.lumileds.com/pdfs/techpaperspres/intertch2000.PDF

   ...y viernes nuevo habañeros, scott35.




[This message has been edited by Bjarney (edited 12-31-2004).]

Also, ever seen the strobe lights installed in some Fort Washington and York PA signals? They install them in the red signal visors and lead the wires through the gasket of the lense? It is a white, horizontal strobe light that flashes extreamly fast.

Ian
(Theelectrikid)

Glad you're still kickin' around!

The Chicago metro area's been changing over pretty heavily over the last 18 months, at least on state highways.

The only local town that's gone the LED route for walk/don't walk standards is Lake Forest (put your pinky up, gent's... they're high class, dont'cha know)

" a 300 millisecond advantage in poor lighting conditions due to their conspicuous, fast turn-on time."

At 60 mph that's a very valuable 26 feet.

A great thing I've noticed about our LED signals is that a section of the lamp can go out and the remainder remains lit, so the signal stays in operation instead of blacking out.

Talking about signals we have a weird one here in Winnipeg. Apparently its a special one that is designed to allow u-turns only. The signals manager was on the TV news a while ago saying its the only one that he knows of in Canada.

From looking at it I think that it is a special lens made up to go over a standard green led fixture. The lens looks like a
u-turn sign with a curved u and arrow pointing down small enough to fit on a signal head.

The intersection that it is on does not allow left turns (east) as its a one way street going west. Because of a shopping center 1/4 block down on the left side going north the traffic department had the idea of allowing traffic going south to make a signal protected u-turn to access it instead of putting in a median cut.

On the Alice Springs to Darwin railway line in the Northern Territory of Australia, all the level crossings (railroad crossings) are fitted with 12" LED lights. The equipment is solar powered (one crossing is ove 50km from the main electricity grid)

mbhydro, does your "weird" signal look something like this one on Baltimore Ghosts?: http://www.btco.net/ghosts/signals/novel/sig_uturnnottghm.jpg

Exactly like that one on the bottom left.

I love this topic there I like LED's in general and their applications.

In Auckland, New Zealand the first LED traffic light set appeared at the Auckland International Airport main road entrance around 2001.
In the last 2 years West Auckland has about ½ of all installations with LED's, some with only the high road lamps with LED's and side lamps with filaments.
The North shore and Central city are fitting the newer installations with LED's now a days but quite often only the high lamps.

You certainly notice the difference in brightness and equal colour and instant snap action during change over with almost a 'black stage' in between.

There is a batch (4) of Orange LED clusters out West with 4 LED's out, all in the same corner of the lamps. must be a manuf. error.

Some railway crossing lamps have LED's now and all the railway signal lamps at Britomart station are fitted with LED's.

We use LEDS in indicator lamps on the mains for the powerboard too, In kWh meters for potential indicators and streetlight and hotwater pilot circuits.

Very reliable LED indicator and better than the pre made ones I find is use:

High eff. LED, 2 x 33kOhm 1 Watt resistor in series, 1N4007 diode in series and 1N914 or eq. diode in antiparrallel with LED.
This yields a current of about 3 to 4 mA through the LED with very good visabilty and excellent lifespan >> 15 years in noisy, spikey electrical environment.
Note this is for 230 volts.
For 115 Volts 2 x 18 kOhms will do or a single 39 KOhms resistor.

I like to underrate the LED's a lot , most are designed for 20 to 30 mA and peaks of 100 mA are allowed. 4 mA is long life guarantied. LED man cheers

In Stockholm Sweden, the first LED lights appeared some five or ten years ago. Most were replaced within a year after that. I remember reading an article about it. Life was so much better and electricity usage so much lower than for the incandescent that the pay back period was very short. (Less than a year IIRC, but don't quote me!)

Talking of funny lights. I saw red and green on at the same time in Italy last year. I wish I had a camera. The green had an arrow pointed straight ahead. I took it to mean "Red for all turns, green for straight ahead"
Any other countries that use this?

[This message has been edited by C-H (edited 12-23-2005).]