Ann Arbor street lights to be replaced with LEDs
By Darren Murph 
posted October 19th 2007 7:01AM
posted October 19th 2007 7:01AM
[Image courtesy of University of Michigan]
posted October 19th 2007 7:01AM
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So this means that in seven years they will start to save money and lower the power consumption to reduce enviromental hazards!? Plus bringing in money and jobs to the LED industry.
Bring it on!
the buckeyes are #1 on the BCS poll. it'll be a long while, says 5-10 years before umich can regain its status in the big 10 (or 11?).
It will be 5-10 more years for Buckeye fans to learn proper grammar.
and the buckeyes are certainly deserving of that #1 spot aren't they? They're more or less there by chance, theyre HIGHLY overrated, and if Michigan State doesn't beat them this weekend, then Michigan will get it done in ann arbor.
um will not beat OSU. Tressel owns carr and will win again this year. um needs to worry about beating minor league 1-aa teams before mouthing off about how they will beat the #1 team in the nation....nuf said!!
Uh, as much as it pains me greatly to state this, but Michigan is still unbeaten in the BigTen.
It also pains me greatly to state that there's also nothing wrong with OSU being #1 "by chance." They were not GIVEN #1 for free - they started out high enough preseason and took care of business every week, which is more than I can say for most other highly ranked teams coming into this year, including my own.
ahh!!! you buckeye fans. That's why you were absolutely smashed by Florida in the title game. And come on, 5-10 years, lets be realistic. This is not an argument you want to get into with Michigan fans. Michigan is the most successful football program EVER!!!!! Nuff said
White and blue LEDs suffer from the "blue light hazard".
Basically white LED-s appear white, but their spectrum differs significantly from that of a black body radiation (conventional light bulb, sun, etc). They have a rather sharp spike in the blue color range.
Blue light between 400 and 500nm has an odd property that our eye photo cells don't recover before absorbing more of the light, and this can lead to eye injury, i.e. this is what "blue-light hazard is".
It'll be interesting to watch the Toronto people suffer from more eye injuries as a results of their city lights being replaced with LED-s.
Ah, thanks for clarifying. I thought it had something to do with shopping at Kmart.
Interesting. Can't a white LED be fitted with a filter to reduce the blue spike?
With modern phosphors and the even better ones in the pipeline, that hazard is not a severe one at all.
Even current warm tint high-flux LEDs have red levels on par with their blue levels.
@John Stracke
The trouble is they emit a narrow blue peak -- you filter that and you have little left.
Where as heat-based lights emit close to black-body, which is (over the narrow gap that is the visible spectrum) flat, or slanted one way, or slanted the other, depending on effective temperature. But _not_ possessing a sharp peak.
The trouble isn't the blue light -- it's the blue light _without_ other colors that causes problems.
Though, as pointed out, new blue LEDs have broader spectra, reducing the hazard.
Also (and I feel this is a very important point), it's Ann Arbor. I'm not sure where you pulled Toronto from.
Aren't there RGB LED's that can reduce the Blue-light hazard?
Would you please stop reporting about LCD streetlights? It's been going on for years (I spotted my first LCD traffic light in 1999, in Philadelphia); it's just not news any more when some city decides to do it.
How are your eyes?
First, it's LEDs, not LCDs, huge difference, and secondly, it makes a huge difference. We're not talking about LED stoplights. Yes, those have been around forever, but we're going about all the street lights. It saves huge amounts of money. LEDs basically never burn out, and use a ton less electricity. One LED light will likely last most of your lifetime, GREATLY reducing the cost of replacing the bulbs, and saving a ton of power all along.
LED, not LCD. And IMHO they're talking about street lights and not traffic lights.
In your humble opinion, eh? It says "street lights" and not "traffic lights". What's there to have an opinion about?
Yes, LED, not LCD; I mistyped.
And, yes, LEDs will save lots of energy. Sure. We know all that. So we *don't* need to hear it again and again on Engadget, every time another city decides it's time to bite the bullet and invest up-front to save in the long term. It's pretty much inevitable at this point, which means it's not news.
Now, LED lighting systems for the home, sure. Those are still expensive enough to be a novelty; as they come down in price, we'll see interesting products built around them. But drop-in replacements for street lights are not interesting.
"LEDs basically never burn out"
Truth is basically do burn out though. Usually they fail gradually vs suddenly so it's harder to notice.
I wish people aren't so quick to jump on the cheap bandwagon before considering the health consequences of lighting the entire city with those things. It's handy as equipment light indicator, street lights and on your cellphone, or as a backup flashlight.
But using it as a primary source of light is harmful.
In a way it's like aspartam: much cheaper than sugar but much less healthy.
@ suv4x4
In what manner are LEDs injurious to health?
Obviously I understand that they DO eventually reach and end of life, but compared to an incandescent bulb, it's life span is incredibly longer. The common number given for LEDs is 60,000+ hours of life, whereas an incandescent gets 1,000-1,500. That means that if you even had just 100 lights (and a city obviously has ton more), you would have to change 60,000 incandescent lights before you had to change the 100 LED lights.
You make it sound like this is something that has been going on for years, but this will be the third city to do a big swap like this. This is technology news that interests some of us. Just because it's not about the latest Apple product doesn't mean no one cares. You sure are spending a lot of time commenting on something you don't care about.
@Andy:
That 60K hour life is in lab conditions (and I've seen numbers as high as 100K hours).
They are sensitive to heat (among other things). There is also the issue of the driver burning out before the actual LED.
Most of my sales reps (I manufacture fixtures) who sell LEDS have seen most of the white colors lasting no more than 20,000 hours.
Look at the warranties for these LEDs. Most companies will not go beyond a year, which is less than 10,000 hours. If they last 60,000 hours, you would expect them to stand behind their products for at least five years.
The other poster is correct... LEDs are ideal for signal, sign, and accent, but for general lighting, they're not ready for prime time. Colored applications take advantage of the energy savings by not having to filter out everything but the color you want -- They just create what you need. This doesn't apply as nicely to white light.
And even longer for the original poster to learn to spell. Maize is the correct spelling.
Regardless, LED lighting sounds like a good idea, perhaps it will offset the cost of the next defeat.
Go Buckeyes!
O-H-
I-O!
OH-NO!
MAIZE and blue, not maze and blue.
See, our colors are yellow and blue, and it all goes back to the 1800s when we used to grow corn, or something. Corn = maize = yellow.
Go Blue!
I'm gonna convert my porch lights to H.I.D's I got from a car shop. This way I can keep the neighborhood on edge with my unnatural brightness.
I wonder if a single AA would be strong enough to light one of these lamps?
Cause we all know what an AA can do against the Maize and Blue :)
does anyone know why street lamps turn on and off all the time?
Because they have ambient light sensors on top. If a flash of light hits that sensor, the light will go off.
I think they have more than that too. Like some way to force them on. Weird as it is, I swear my radar detector screws with them. On countless occasions I've driven under a light and it turned off. Pretty weird.
and some of the streetlights, i think, are mercury vapor lamps, and some of those take a few minutes before they come up to full brightness, something having to do with heating up i think. Also the flickering of the light could mean a bad connection, but more than likely its either going bad, or the light sensor is going bad or has some thing interfearing with it. With the LED night lights if they get there own light reflected back at the sensor just right it'll start blinking,the light gets reflected onto the light sensor, turning the light off, the light goes off the sensor gets trigged to turn the light on, and it starts over again
There right about the sensor killing the light. When i was younger i used to take a laser pointer an point it at the top of the post. You have to be pointing from above the top of the light in order to hit the sensor. Sometimes a maglite will work too. just focus it to the strongest beam possible.
Cities have timers in them that will turn one off on a street full of them for a while, then alternate to another. It's a way to reduce the amount of power consumed on any given night.
Sodium vapor lights (the ones with a yellow color) will cycle on and off when they get to the end of their life. They have burned out at that time and need to be replaced.
Sodium vapor lights (the ones with a yellow color) will cycle on and off when they get to the end of their life. They have burned out at that time and need to be replaced.
There are few incandescent street lights in operation anywhere because of the short life. They have been replaced with mercury vapor or sodium vapor lights with a life of about 20,000 hours, or metal halide lights with a life of about 10,000 hours.
GO BUCKS!!!
OSU overrated? Possibly, but at least we beat the teams we are supposed to, like 1-AA Football teams.
Michigan sucks
OSU is not possibly overrated, they are overrated. And even though we may lose a game like the Appalachian State game once in awhile, we still hold the most winningest record in all of college football.
Go Blue!
"...we still hold the most winningest record in all of college football."
But it's different coaches, different players, different everything. It's really about the here and now.
It's sad when you have to add up decades of results to offset current conditions. Face up to the facts - If history is all you've got, then you're living in the past!
What you guys fail to consider is that yes, LEDs are efficient light sources- but how efficient? The newest high-flux white LEDs coming out of the likes of Cree and such achieve approximately 70 lumens/W. This is very efficient, however when you compare that efficiency to existing lamp technology such as metal halide (approx 90 lumens/W) and high pressure sodium (over 110 lumens/W), LEDs do not come out on top. Additionally each LED lamp will cost many times more than the equivalent standard metal halide fixture because of the new, specialised nature of the lamp.
LEDs are getting there, and they are beginning to become useful in architectural lighting contexts, however they are not efficient enough to use them for public street lighting in my opinion. Sounds like Cree have subsidised this project anyway...
The new Crees and Luxeon Rebels beat 100lm/W at 350mA.
The higher bin Crees on the horizon (R-bin) will be even better.
I think more could be gained by designing the fixtures to project the light in the correct directions, rather than through the gaps in my blinds and onto my face when I'm trying to sleep on my couch.
I-O!!
Ah - never thought I'd see my love of technology and college football combined.
As far as it being a few years before Carr (or his replacement) beats the Buckeyes - it will be at least that. If the Big 10 is "weak" like the talking heads (Lee Corso I'm giving you my evil eye) like to say - then being unbeaten in the big 10 isn't a big deal - you have to look at the non-conference games. UM lost to App. State (who??) and OSU beat Washington quite handily (in fact they man-handled them easier than USC who was ranked #1 at the time!). It would be a great shock to me if UM beats OSU this year. If anyone has a chance it may be PSU ... but I'm not worried.
But then again - who thought USC would lose to Stanford? Oh yeah - Big 10 (and SEC too probably) fans that always think USC is over-rated.
One thought that occurs to me about the OLEDs... "this will last an entire lifetime" I wouldn't base financial decisions on that fact. After all - some original Model T drivers still drive their car - but the vast majority of us don't hang onto a car or anything else our whole lives. There will be a new lighting technology eventually that is cheaper, longer-lasting, etc. How long do those UM LEDs have to be operating before the cost savings cover the installation costs? According to the numbers in the article it could be seven years or more..... Where it will get sticky is when LEDs start popping up (monitors..) in other sectors that replace their parts more often not out of necessity - but to stay "current." Would you pay triple the price for a monitor that will last your whole life?
But hey, if UM (and Toronto) wants to be the test mule for the rest of the world - be our guest!
I'm so glad Ann Arbor is much more than football.
I mean, they're talking about lighting an entire city this way (and as a Michiganian, it's my favorite city in my state, by the way) yet we've got numerous people talking about something that takes place in a mere 100+ yards of the city.
What I'm saying is WHAT DOES BIG 10 FOOTBALL HAVE TO DO WITH THIS ARTICLE?!?!
Nothing? Oh, I see. It's just whenever anyone talks about a town like Ann Arbor or Lansing, all they know about it is the damned college sports team.
Ann Arbor is a lot more than a college town. It's the home base for a lot of forward-thinking companies (Google, Borders, etc.) and it's the most progressive city in the midwest. It's a nice place to live-- People do LIVE there, you know.
The way some of you talk, you'd think Ann Arbor is just the University of Michigan's football team surrounded by some street lights.
And please-- Stop with the whole "Wolverines" thing. It's an ancient, antique of a nickname for Michigan natives, and the sports teams don't help a whole lot. There hasn't been an wolverine in Michigan for over a hundred years, if ever (some say we never actually had them here.)
And as much as I find Ohio to be weird and backwards sometimes, they aren't just the fricking Buckeyes. There are lots of interesting things and people in Ohio... Not just sports.
And the best thing about Michigan and Ohio..?
Neither of us is Indiana.
I currently live in Ann Arbor, but I grew up in Indiana... Your words hurt me.
I guess you didn't pay attention to the news... a wolverine was photographed in 2004 in Ubly... http://www.msnbc.msn.com/id/4374309/