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National Boards => General Highway Talk => Traffic Control => Topic started by: Roadman66 on November 04, 2011, 10:51:58 PM

Title: NYC traffic lights
Post by: Roadman66 on November 04, 2011, 10:51:58 PM
Why did NYC boroughs change their traffic lights to LED lighting? Better question, how come several states are switching over to LED lighting for traffic lights? NJ, PA, DE, FL, MD you name it. I enjoy the old lighting.
Title: Re: NYC traffic lights
Post by: NE2 on November 04, 2011, 11:33:46 PM
Power consumption is more important than your personal desires.
Title: Re: NYC traffic lights
Post by: Scott5114 on November 05, 2011, 12:36:38 AM
LEDs do consume less power, and the diodes last far longer than any incandescent bulb.

Eventually, as the cost comes down, LEDs will probably start replacing incandescent and fluorescent bulbs in many other places, not just stoplights. I work on slot machines, and a lot of the newer models have replaced the fluorescent tubes used to light up the machine glass with strips of LEDs. Smaller, less prone to flicker, less breakable, less power-hungry...pretty much objectively superior in every way.
Title: Re: NYC traffic lights
Post by: Quillz on November 05, 2011, 01:48:22 AM
As I noted in another topic, this isn't an isolated incident. California is also beginning to install LED lights. They are brighter, cheaper and last far longer.

Yes, they do look a bit awkward, but it's one of those things that will grow on you once you see them hundreds and hundreds of times over the next few years.
Title: Re: NYC traffic lights
Post by: Brian556 on November 05, 2011, 09:53:19 AM
Not only do they consume less power, but they produce much stronger colors, which looks better. Almost all of our signals in Texas are LED. I drove into Tennessee at night a year ago and it was weird seeing all incandecents. I though to myself: "Man, this place is stuck in the past".
Title: Re: NYC traffic lights
Post by: US71 on November 05, 2011, 10:37:19 AM
Quote from: Scott5114 on November 05, 2011, 12:36:38 AM
LEDs do consume less power, and the diodes last far longer than any incandescent bulb.


In theory, at least. Fort Smith has been changing over for the last 2-3 years and even more so this last Summer. Yet, some of the signals already have diodes that have burned out, leaving odd "streaks" across the lens.

I have noticed on some signals, you can see the individual LED's. On others, you can't... just the signal lens.
Title: Re: NYC traffic lights
Post by: Duke87 on November 05, 2011, 11:15:17 AM
Quote from: US71 on November 05, 2011, 10:37:19 AM
Quote from: Scott5114 on November 05, 2011, 12:36:38 AM
LEDs do consume less power, and the diodes last far longer than any incandescent bulb.

In theory, at least. Fort Smith has been changing over for the last 2-3 years and even more so this last Summer. Yet, some of the signals already have diodes that have burned out, leaving odd "streaks" across the lens.

This is a symptom of manufacturing defects. Good quality LEDs should last at least 100,000 hours of burn time (that's 11½ years if on constantly).

Title: Re: NYC traffic lights
Post by: roadman65 on November 05, 2011, 11:36:15 AM
Quote from: Roadman66 on November 04, 2011, 10:51:58 PM
Why did NYC boroughs change their traffic lights to LED lighting? Better question, how come several states are switching over to LED lighting for traffic lights? NJ, PA, DE, FL, MD you name it. I enjoy the old lighting.

LED lights are basically cost effiecient!
Title: Re: NYC traffic lights
Post by: thenetwork on November 05, 2011, 01:27:21 PM
Quote from: Quillz on November 05, 2011, 01:48:22 AM
Yes, they do look a bit awkward, but it's one of those things that will grow on you once you see them hundreds and hundreds of times over the next few years.

In my neck of the woods, nearly all the traffic lights are now LEDs.   The few "endangered" intersections of non-LED signals are now my favorite...I never realized how much I liked the old lights which have that "soft switch" look when the lights would change color.

The newer LED lights, while being very nice and bright, are too crisp or strong when they change color.  In other words, the new lights don't have that fraction of a second when the bulb would fade-in or fade-out when changing anymore.  Occasionally, there are a few intersections in which there is a brief millisecond when the lights are all out between changes, that looks cool, but the bottom line is that they don't have that gentle phasing like they used to.  Same thing can be said for older flashing beacons.

It's true what they say that sometimes you don't realize how good something is until it's (almost) gone.  :-(
Title: Re: NYC traffic lights
Post by: Quillz on November 05, 2011, 01:49:26 PM
Quote from: US71 on November 05, 2011, 10:37:19 AM
Quote from: Scott5114 on November 05, 2011, 12:36:38 AM
LEDs do consume less power, and the diodes last far longer than any incandescent bulb.


In theory, at least. Fort Smith has been changing over for the last 2-3 years and even more so this last Summer. Yet, some of the signals already have diodes that have burned out, leaving odd "streaks" across the lens.

I have noticed on some signals, you can see the individual LED's. On others, you can't... just the signal lens.
Just bad diodes due to poor manufacturing. Although, there will always be a certain small number of bad diodes that are considered tolerable, similar to "dead pixels" on either a computer or television display.
Title: Re: NYC traffic lights
Post by: Revive 755 on November 05, 2011, 02:42:31 PM
^ It seems to be more related to the design of the lens.  Some traffic lights have a lens that disperses light from the LEDs more, while others just have a clear sheet of plastic between the board with the LEDs and the motoring public.
Title: Re: NYC traffic lights
Post by: Dr Frankenstein on November 05, 2011, 04:33:55 PM
The MTQ made the switch too. New or replaced signals use LEDs.

In fact, it's been a while, because there are many shaped-lens signals which use LEDs.
Title: Re: NYC traffic lights
Post by: roadman65 on November 06, 2011, 01:25:31 PM
You know when the standard orange mercury lighting came out, I hated it!  Now they grew on me and so will these new different lighting at signals.
Title: Re: NYC traffic lights
Post by: Duke87 on November 06, 2011, 05:35:09 PM
Quote from: roadman65 on November 06, 2011, 01:25:31 PM
You know when the standard orange mercury lighting came out, I hated it!  Now they grew on me and so will these new different lighting at signals.

The orange lighting is High Pressure Sodium (HPS). Mercury Vapor lamps glow cool blue/green. They're pretty much extinct nowadays (been illegal to install them new for years), although I did see some in a parking garage in White Plains recently (which should be getting replaced as I type this).
Title: Re: NYC traffic lights
Post by: SignBridge on November 06, 2011, 08:31:05 PM
Illegal? Are you sure about that Duke? Within the last 10 years, in Mineola, Long Island  new mercury vapor lamps were installed on the new Mineola Blvd. overpass over the L.I. Railroad. I was surprised, but that's what they have. Also many private parking lots, especially at shopping centers still use mercury vapor lamps, some quite new.

Pardon my skepticism over the word "illegal". I've been told many things thru the years by many people about what was legal and illegal and most of those people didn't know what they were talking about when I researched whatever subject it was.  
Title: Re: NYC traffic lights
Post by: roadman65 on November 07, 2011, 06:01:43 PM
Quote from: Duke87 on November 06, 2011, 05:35:09 PM
Quote from: roadman65 on November 06, 2011, 01:25:31 PM
You know when the standard orange mercury lighting came out, I hated it!  Now they grew on me and so will these new different lighting at signals.

The orange lighting is High Pressure Sodium (HPS). Mercury Vapor lamps glow cool blue/green. They're pretty much extinct nowadays (been illegal to install them new for years), although I did see some in a parking garage in White Plains recently (which should be getting replaced as I type this).

Turkey Lake Road in Orlando, FL next to Universal Studios has the old mercury lighting.  It was to resemble Hollywood Boulevard or one major road in Hollywood, CA that uses (or did use them in 88 when I was there) and still Orlando has them there 22 years later. 

CR 532 in Osceola County, FL uses them with antique looking posts where it was widened to four lanes near I-4.
Title: Re: NYC traffic lights
Post by: Duke87 on November 07, 2011, 06:38:38 PM
Quote from: SignBridge on November 06, 2011, 08:31:05 PM
Illegal? Are you sure about that Duke? Within the last 10 years, in Mineola, Long Island  new mercury vapor lamps were installed on the new Mineola Blvd. overpass over the L.I. Railroad. I was surprised, but that's what they have. Also many private parking lots, especially at shopping centers still use mercury vapor lamps, some quite new.


They were banned effective 2008 by a law passed in 2005. (http://mercuryvaporlight.com/banned-Mercury-Vapor-Lights/energy-policy-act-of-2005.html)
Title: Re: NYC traffic lights
Post by: nyratk1 on November 07, 2011, 07:51:32 PM
Quote from: Scott5114 on November 05, 2011, 12:36:38 AM
LEDs do consume less power, and the diodes last far longer than any incandescent bulb.

Eventually, as the cost comes down, LEDs will probably start replacing incandescent and fluorescent bulbs in many other places, not just stoplights. I work on slot machines, and a lot of the newer models have replaced the fluorescent tubes used to light up the machine glass with strips of LEDs. Smaller, less prone to flicker, less breakable, less power-hungry...pretty much objectively superior in every way.

And quite a bit more flexible in terms of traffic usage. It's a lot easier to have things like bimodal arrows and countdown pedestrian signals now.

Also most of the LED fixtures where you can see individual LEDs are going the way of the dodo with the exception of some arrow, lane control and pedestrian displays. Most manufacturers offer incandescent style LED fixtures now.
Title: Re: NYC traffic lights
Post by: SignBridge on November 07, 2011, 08:34:10 PM
Thanks Duke. I did some checking and it seems you are correct. I hadn't heard this before. Those streetlights installed in Mineola are from around 2003. I don't know why they used mercury vapor instead of sodium vapor.
Title: Re: NYC traffic lights
Post by: architect77 on November 09, 2011, 07:31:45 PM
North Carolina started an initiative back in 2005 to convert every signal in the state to LED's, stating that they used only a fraction of power of the incadescents and lasted many times longer.
Title: Re: NYC traffic lights
Post by: vtk on November 10, 2011, 06:44:28 PM
A recent edition of the Franklin County, OH official map states that all (county-maintained) traffic lights in the county are being upgraded to LEDs.
Title: Re: NYC traffic lights
Post by: Ian on November 10, 2011, 07:58:21 PM
I've noticed that there still is a surprisingly large amount of incandescent signals left in Maryland. Last time I was there (this past June), about half the signal installs I've seen were incandescent.
Title: Re: NYC traffic lights
Post by: SignBridge on November 10, 2011, 08:37:22 PM
Sometimes it's hard to recognize LED lights. Some of us recently found out that there are different kinds of lenses used. On some you readily see the LED honeycomb when the light is lit. But on others, there is almost no noticable difference from an incandescent type. So you might not know it's been changed to an LED light.
Title: Re: NYC traffic lights
Post by: US71 on November 10, 2011, 09:25:19 PM
Quote from: SignBridge on November 10, 2011, 08:37:22 PM
Sometimes it's hard to recognize LED lights. Some of us recently found out that there are different kinds of lenses used. On some you readily see the LED honeycomb when the light is lit. But on others, there is almost no noticable difference from an incandescent type. So you might not know it's been changed to an LED light.

LED's appear to change faster... not as much "afterglow".
Title: Re: NYC traffic lights
Post by: Ace10 on November 15, 2011, 09:52:59 PM
If you look closely at the lens, you can easily tell. If it looks like a very smooth lens with no texture, it's most likely LED. If you see circles or lines (that look like a Fresnel lens) it's most likely incandescent. Also a bunch of incandescent signals in my area have a dark dot in the very center - like the incandescent light is so hot, it burned the middle of the lens!
Title: Re: NYC traffic lights
Post by: surferdude on December 30, 2011, 12:31:02 AM
I know in PA, PennDOT is not resposible for maintaining the traffic signal after it is installed.  That responsibilty falls on the Township/Borough/City that the traffic signal is located..  The cost in savings is two fold, first electricty usage will go down and the second is less replacement of incadencent bulbs which they are not cheap to replace and have to hire a contractor to come out and install the new bulbs.  There is some other major benefits like the signal being brighter and one can also see it in the sun, which is a safety concern when sun is behind the singal.  I know that there is a problem in the winter with them being iced over since they generate virtually no heat and happens in Minnesota and Wisconsin (I think).  I have also seen them in OH and NY. 
Title: Re: NYC traffic lights
Post by: M3019C LPS20 on March 15, 2013, 07:01:38 PM
Simple reason. Energy consumption.

Originally, N.Y.C.D.O.T. replaced incandescent red and green signal indications with red and green L.E.D. module inserts. The amber indications were untouched, due to the reason that they were not illuminated for a long period of time (only a handful of seconds). Although it was not until in later years that a new requirement was established. A new traffic signal must have all three L.E.D. indications. The older traffic signals that still have incandescent amber indications are fine, but when one dies, it'll ultimately be replaced with a L.E.D. module insert.

The city's D.O.T. originally installed Cooper L.E.D. module inserts, which are not exactly great signal indications. One has a lifespan of typically seven years. Most in New York City have reached the end, and many have been replaced over the years.
Title: Re: NYC traffic lights
Post by: SignBridge on March 15, 2013, 08:03:11 PM
Where is that new requirement? Is it in the 2009 MUTCD and would you know the section?
Title: Re: NYC traffic lights
Post by: M3019C LPS20 on March 15, 2013, 09:32:14 PM
Quote from: SignBridge on March 15, 2013, 08:03:11 PM
Where is that new requirement? Is it in the 2009 MUTCD and would you know the section?

I would not know, since I once had a short conversation with a technician from the city several months ago.
Title: Re: NYC traffic lights
Post by: vdeane on March 16, 2013, 11:49:04 AM
Quote from: SignBridge on March 15, 2013, 08:03:11 PM
Where is that new requirement? Is it in the 2009 MUTCD and would you know the section?
Why would it be in the MUTCD?  The MUTCD regulates what information is displayed.  It does not regulate energy consumption.  This would be a city or state law.
Title: Re: NYC traffic lights
Post by: Duke87 on March 16, 2013, 04:50:13 PM
Yeah, sounds like just DOT policy. But still, makes perfect sense. If you're going to go through the bother of replacing a signal head, might as well make the whole thing LED. The business of replacing just the red and later the green (this has been done by many jurisdictions all over the country, by the way, not just New York City) was retrofitting existing heads with new lamps.
Title: Re: NYC traffic lights
Post by: SignBridge on March 16, 2013, 04:54:54 PM
Well Deanej, he said a new traffic signal requirement. Those are normally in the Manual. And if it was, I would want to check it for myself, since so much misinformation gets talked about re: what is or is not in both the MUTCD and state traffic laws. That's why I keep a current copy of both the MUTCD and the NYS VTL, so I can read and verify for myself, okay?   :biggrin:
Title: Re: NYC traffic lights
Post by: M3019C LPS20 on March 16, 2013, 07:00:01 PM
Quote from: SignBridge on March 16, 2013, 04:54:54 PM
Well Deanej, he said a new traffic signal requirement. Those are normally in the Manual. And if it was, I would want to check it for myself, since so much misinformation gets talked about re: what is or is not in both the MUTCD and state traffic laws. That's why I keep a current copy of both the MUTCD and the NYS VTL, so I can read and verify for myself, okay?   :biggrin:

I apologize for the confusion.

The technician that I talked to a couple of years ago mentioned this requirement to me. I didn't specifically ask him if this is merely a requirement from N.Y.C.D.O.T., but it is likely. It was at the spur of the moment. New York City developed interesting things over the years. One of them that I am fond of is the left turn on red (if posted).
Title: Re: NYC traffic lights
Post by: SignBridge on March 16, 2013, 09:38:20 PM
No problem; I was just trying to pin down the source and answer deanej's question.
Title: Re: NYC traffic lights
Post by: vdeane on March 17, 2013, 11:08:42 AM
Quote from: SignBridge on March 16, 2013, 04:54:54 PM
Well Deanej, he said a new traffic signal requirement. Those are normally in the Manual. And if it was, I would want to check it for myself, since so much misinformation gets talked about re: what is or is not in both the MUTCD and state traffic laws. That's why I keep a current copy of both the MUTCD and the NYS VTL, so I can read and verify for myself, okay?   :biggrin:
The Manual also relates to the information displayed on traffic control devices, of which LED vs. incandescent is not a part.
Title: Re: NYC traffic lights
Post by: M3019C LPS20 on May 07, 2013, 01:10:53 AM
I recall that after the L.E.D. conversion in New York City in the early 2000s, the city continued to install and use the incandescent amber indication in new traffic signal heads that the city installed. Red and green indications were each L.E.D., of course. It was a common practice for quite a while until the mid 2000s or so.