LED Lighting

[MichiganDriver]

MDOT is putting in LED's on the reconstructed M-39, as far as I know these first on a state highway and from what've I've seen I love them. There're already on from Ford Rd. to about Grand River even just on traffic cams they make a big difference in brightness and clarity. So where else LED going in?

http://mdotnetpublic.state.mi.us/drive/

[Quillz]

Wasn't New York experimenting with some sort of LED lighting in the roadway, to help illuminate the dividing line during the night or during snowstorms?

[roadfro]

It sounds like the OP was referring to overhead LED street lighting (as opposed to the current standard of high-pressure sodium vapor or mercury vapor lighting).


As far as I know, no jurisdiction in Nevada is making a wholesale conversion to LED streetlights. Washoe County RTC got some grant funding to replace nearly all street lights at signalized intersections in the Reno-Sparks area with LED fixtures. It's interesting because so many intersections have gone from the bright yellow/orange of high pressure sodium lighting to the bluish-white of LED fixturess. I think the replacements make intersections look darker, but that's probably due in large part to the LED fixtures focusing light more straight down, whereas the old cobrahead fixtures were domed so the light bled out in more directions.

[SSOWorld]

Wasn't New York experimenting with some sort of LED lighting in the roadway, to help illuminate the dividing line during the night or during snowstorms?

If I remember the GWB has LED lampposts on it - also the suspension cable is lined with LED lamps.  I can say this first hand from crossing it during the night in Aug 2010.

[1995hoo]

I remember reading a news item last year after the massive East Coast snowstorm in February about how LED lighting poses a bit of a problem in heavy snow because the bulbs don't generate enough heat to melt snow and ice.

[Ian]

MaineDOT is going to start (if they haven't already) to use LED lighting at their freeway interchanges. Haven't seen any out in the field yet elsewhere.

[realjd]

I remember reading a news item last year after the massive East Coast snowstorm in February about how LED lighting poses a bit of a problem in heavy snow because the bulbs don't generate enough heat to melt snow and ice.

That's only really a concern with LED traffic lights though. Or is snow really able to accumulate on the bottoms of street lights?

[MichiganDriver]

It sounds like the OP was referring to overhead LED street lighting (as opposed to the current standard of high-pressure sodium vapor or mercury vapor lighting).


As far as I know, no jurisdiction in Nevada is making a wholesale conversion to LED streetlights. Washoe County RTC got some grant funding to replace nearly all street lights at signalized intersections in the Reno-Sparks area with LED fixtures. It's interesting because so many intersections have gone from the bright yellow/orange of high pressure sodium lighting to the bluish-white of LED fixturess. I think the replacements make intersections look darker, but that's probably due in large part to the LED fixtures focusing light more straight down, whereas the old cobrahead fixtures were domed so the light bled out in more directions.

Yeah, I was talking more so about street lighting. What you say about spreading light seems very true the M-39 service drive lights are out and the new lights don't help much at all.

[txstateends]

In Addison, a Dallas suburb, street light poles that get hit by cars or otherwise damaged are being replaced with new-style poles which all have LED lighting (the existing ones have had sodium vapor).  Not sure whether I like them yet or not.  They don't seem bright enough.

IINM, parking lot lights at several Dallas-area 7-Eleven stores have gone LED also.

[Ian]

I remember reading a news item last year after the massive East Coast snowstorm in February about how LED lighting poses a bit of a problem in heavy snow because the bulbs don't generate enough heat to melt snow and ice.

There is a traffic signal company that came of with the idea of "snow scoop" visors, which are ordinary signal visors that have vents in the top of them to prevent snow build up. So far, I've only seen them in place in Wilmington, DE.

[iwishiwascanadian]

Charles Street north of Hopkins in Baltimore has LED lights installed. 

[roadfro]

I remember reading a news item last year after the massive East Coast snowstorm in February about how LED lighting poses a bit of a problem in heavy snow because the bulbs don't generate enough heat to melt snow and ice.

There is a traffic signal company that came of with the idea of "snow scoop" visors, which are ordinary signal visors that have vents in the top of them to prevent snow build up. So far, I've only seen them in place in Wilmington, DE.

I don't know how a vent in the top helps prevent snow accumulation... The easy thing to do is use 3/4 visors (used on newer signals in Reno) or cutaway visors, which both have no area on the bottom for snow to accumulate.

[jjakucyk]

I don't know how a vent in the top helps prevent snow accumulation... The easy thing to do is use 3/4 visors (used on newer signals in Reno) or cutaway visors, which both have no area on the bottom for snow to accumulate.

They attempt to channel some of the wind over the face of the signal to help blow the snow away.  The problem is wind-driven snow in the first place that sticks to the lens.  Cutaway visors don't help as much either since the snow also sits on the top of the visor below (so while the green may be clear, the yellow and red won't be).  It really only seems to be a problem with heavy wet wind-driven snow, while the more powdery stuff just blows away. 

As for LED street lights, I like that they're actually white.  The orange glow of sodium vapor, or the blue/green of older mercury vapor lights are both so unpleasant.  They installed a few test cobra head replacements on one street here in Cincinnati, and they're plenty bright and have good color.  The only complaint I have is that the LED elements are bare with just a clear piece of glass and no shielding, so they cause a lot of glare.  A slightly frosted lens, or recessing the elements or putting some baffles around the sides would help with that. 

[MDRoads]

I've forgotten where I saw it (possibly in one of the NJ towns), but there was an LED signal where the arrow changed colors in place. In other words a standard 3 stack with the green arrow below, and the arrow at the bottom changed from green to yellow without changing position, where you would expect a doghouse configuration to achieve that.   Would have thought this would be a no-no due to possible color-blindness issues.

[Scott5114]

I've forgotten where I saw it (possibly in one of the NJ towns), but there was an LED signal where the arrow changed colors in place. In other words a standard 3 stack with the green arrow below, and the arrow at the bottom changed from green to yellow without changing position, where you would expect a doghouse configuration to achieve that.   Would have thought this would be a no-no due to possible color-blindness issues.

I've seen similar signals in suburban Kansas City in the mid 2000s. They have since been prohibited by the MUTCD on the grounds you mentioned, I believe.

[roadfro]

^ The operation described I believe is prohibited in the MUTCD. However, the 2009 MUTCD does allow a green/yellow bi-modal arrow section for flashing yellow arrow operations--the green and flashing yellow arrows are in the same signal section but the steady yellow is separate. The intent is to allow this where space restrictions wouldn't work for a 4-section head, but I understand areas of Oregon used (uses?) the 3-section variant quite a bit.

[Rick1962]

I've seen similar signals in suburban Kansas City in the mid 2000s. They have since been prohibited by the MUTCD on the grounds you mentioned, I believe.

There are still some bi-modal arrows in use in Johnson County, Kansas. They are also used many places in Enid, Oklahoma.

[hm insulators]

The neighborhood in Sylmar, California, where my friend lives has had a few lights converted to LEDs. They do direct more light downward, which is a good thing. Street lights that shine uselessly outward waste a lot of electricity and create "light pollution," which can have adverse effects on some people's health.

[Quillz]

They're appearing all over the S.F. Valley now. Got to say that aesthetically, I don't like them as much as the old "cobra head," but I'm sure I'll get used to them as I see them more and more often. I don't know who makes them, but here is the design the city is using (there are probably other LED lamps with a different shape):



They apparently make a big lighting difference. Here's the 6th Street Bridge, before and after:



So the light is much more white than yellow. And, being LEDs, they should be both brighter and far more energy efficient, saving a lot of money in the long run. All in all, I think it's a positive change.

And here's an article on the change, seems the whole city is getting them eventually: http://www.sustainablebusiness.com/index.cfm/go/news.display/id/17696

[Tarkus]

^ The operation described I believe is prohibited in the MUTCD. However, the 2009 MUTCD does allow a green/yellow bi-modal arrow section for flashing yellow arrow operations--the green and flashing yellow arrows are in the same signal section but the steady yellow is separate. The intent is to allow this where space restrictions wouldn't work for a 4-section head, but I understand areas of Oregon used (uses?) the 3-section variant quite a bit.

Actually, the 3-section FYAs are becoming extremely common in Oregon.  Washington County went on a major FYA spree last year and replaced a bunch of standard protected left signals with 3-section FYAs.  There's literally hundreds of them now, and they seem to be the standard fixture there now.  ODOT is still using 4-section ones to my knowledge (the ones installed along I-5's exits at Kuebler Blvd in Salem and US-20 in Albany are 4-section).  I wouldn't be shocked to see them switch to 3-section, though it may become standard procedure for them to use 4-sections simply to differentiate from protected left turn signals (not unlike the tendency to use 3M fresnels for all left turn signals before about 1993).

[sp_redelectric]

Actually, the 3-section FYAs are becoming extremely common in Oregon.

For all that ODOT tries to be standardized and is generally pretty good about it, the lack of standardization in Oregon for permissive left-turn signals annoys me to no end.  I first saw the signals in Montana (2000-2002) and they were all of the exact same configuration...Oregon seems to have at least a half-dozen different styles:

The Doghouse (separate left turn and straight amber/green aspects beside each other but a common red aspect)
The Five-Section (separate left turn amber/green below the straight amber/green and a common red)
The Four-Section
The Three-Section

And with the Four- and Three-Section lights there are multiple configurations that include flashing yellow arrow, or solid green arrow, some that have arrows that change colors and some that don't...

[iwishiwascanadian]

Baltimore City has been putting them up all over the place now.  You can mainly find them in the north part of the City especially on the JFX (I-83) between the City/County line and Cold Spring Lane.  They are also on the Hanover Street Bridge. 

[M86]

Springdale, Arkansas has been installing them at signalized intersections... but, in general, roadway lighting is only provided at signals there.  Sigh.

[tchafe1978]

I just noticed some LED streetlighting last night in Madison, WI along Mineral Point Rd. It was my first time seeing it. There was a stretch that had the new LED lighting, and then a stretch that had to sodium lighting, so it was easy to compare. I like the LED lighting, it's brighter, whiter, and easier to see detail in.

[JREwing78]

It appears they installed it on a stretch of Park St just north of the Beltline in Madison as well.