We recently got them in my neighborhood in North Seattle and they work well. The light is blue-er than the old lights they replaced -- to the point that when I glance outside at the street at night my brain says "oh it's snowing!" Nope, just the new LED lights. A few months back, I came home from work and there were all these people on the street in a total downpour. I asked them what was going on and they were a group of folks -- lighting Engineers I believe, who had come from all over the country to check out our LED streetlights. He told me we were one of the first neighborhoods in the U.S. to get them. Pretty fancy for a street that doesn't even have natural gas.

We have a jogging path lit by 100W LED streed lamps near where I live. Havent seen the lights in action yet, I guess all the more reason to take up running again:)

Good to know! The problem with LEDs is always... starting: if a city begin, I'll think that many others will follow soon.
Does anybody knows if there are some other "best practice" or planning about te use of LEDs for public illumination?
Anny

Good to know! The problem with LEDs is always... starting: if a city begin, I'll think that many others will follow soon.
Does anybody knows if there are some other "best practice" or planning about te use of LEDs for public illumination?
Anny

the budget in our town is so tight this year they are turning off 20% of our street lights... seems like LED could (in the long run) save the day. Then again some people will enjoy the lower levels of light pollution.

Finally, every time I see a street light with an old incandescent bulb I wonder how long it would take for an led to pay for itself in energy savings.

"Finally, every time I see a street light with an old incandescent bulb I wonder how long it would take for an led to pay for itself in energy savings."

A long, long time. Typically, street lights are lamped with 100W-400W High Pressure Sodium lamps. Most LED units being looked at for roadway lighting projects require more or less the same wattage of what they are replacing to do the same job of an HPS lamp.

From what I understand of it, one of the major driving factors behind the installation of LED roadway fixtures isn't necessarily energy savings (at least not yet), but instead the lower anticipated maintenance costs associated with the LED fixtures.

I think LED streetlighting is definitely coming. However, it is still a ways off. But once the efficacy of the LED's improves and the cost hopefully lowers, I'm sure most of the US will see installations going up.

Basically, what ocdb said. Current street lamp technology (high pressure sodium, similar to HID) is way more efficient than LED.

With the right heat-sinking though, and lower wattage and output, the electrical operating costs could be the same, while the maintenance costs over the long run will be much cheaper.

HPS/HID may be more efficient than LED, but they still require a "bulb" which can and does burn out and require replacing every once in a while.

LED's will overtake HPS/HID in efficiency some day, but that day is still a few years off.

Theoretical efficiency is lower for LED, but doesn't directionality make up for it? You have less total visible light for a certain wattage, but that light it where you want it and less is wasted.

No?

I recently read an article about a country that started changing traffic lights over to LED's, and they paid for themselves in like 6-9 months, part of which was less time to replace bulbs that burn out.

Not cheap to send a crew up a lift to replace all of those bulbs.

I think it's Mercury Vapor (or Metal Halide, white color) they are going to replace, not HPS (orange light). MV has a low lm/W (Lumen per Watt) compared to HPS, and new LEDs tend to be more like HPS lm/W wise. Another reason to change might be safety, since LEDs will be applied in rows, so there are lots of them and if a single one breaks, only one of say 8 rows die. There will still be light, just a bit less.

Everyone is neglecting to talk about one of the big problems with LED street lights that have been developed so far - GLARE! My retinas are still seeing dot patterns after having seen dozens of these glare bombs at Lightfair last week. And that was on a brightly lit tradeshow floor. We have viewed a mock up of an LED street light in a dark laboratory mounted about 20' above the ground and it was disappointingly blinding. The illuminance distribution and color on the ground was working well, but that will all be defeated if the fixtures produce an unacceptable amount of glare. Imagine driving a car with dozens of these in your peripheral view. Manufacturers - please focus on controlling glare at the same time as delivering light. You will then have a hands-down argument for having municipalities convert to these promising sources for street lighting.

Instead of guessing if leds will take over street lights why not actually search and find out? The comment on leds taking up as much power as a sodium powered light is crazy. Here is a site to check up on funded by the government that shows the latest and greatest led lighting projects. The faster we adopt this technology the faster the prices go down..

http://www.netl.doe.gov/ssl/techdemos.htm

Once you understand the principle of Scotopic Enhanced Lighting, you will understand that high pressure sodium is not as efficent as people think it is. Scotopic Enhanced LED Lighting looks brighter and you see things more clearly than you can with high pressure sodium using the same amount of energy. LED's can put more lighting energy in the right wavelengths of light for the human eye, so they are more efficent. With LED's you can get more Scotopic Lumen's per Watt.

In Rotterdam, The Netherlands, there's an experiment with green LED street lights. The wavelength of the light allows the human eye to discern colors wheres the old "orange" light doesn't.
There's a small article (in Dutch) on:
http://www.energiebesparinggww.nl/index.asp?rf_nr1=600&rf_nr2=0&rf_cat=3&rf_rec=308

May be a good idea to follow the German example, on many levels, including the prohibition of plastic bags in all stores and super markets.

LED street lights are a great idea.

I want to see home use Led Bulbs that screw into a regular fixture.
These will last longer and are worth more. They also don't have pollution problems at life's end. Compact fluorescent light bulbs now contaminate the environment with 30000 pounds of mercury each year.

The color output needs adjusted by including a range of colors in the matrix to give a pleasing range. Also, we need to see a variety of styles and lumen outputs. Once designed and in production these bulbs should be cheap to produce, and easy to sell.

Good to see the usage of Led taking place, one of these days I have a nice garden indoors all year around and possible using guilt free solar power.. Fresh salads nightly.. ahh.. pass me the vinegar..

I cannot wait till our town completely phases in LED for traffic lights, and other driver notification devices. I also would love to have LED street lights, but no word on that yet.

I've been in the lighting industry for a long time and have seen many positive changes in both lighting practices and technology. LEDs have begun to grasp a decent market-share of low level lighting such as step lighting as well as landscape lighting and other low ambient light applications. We're beginning to see municipalities test the technology for broader area lighting which is important to furthur the technology, however before everyone gets too crazy and wants to replace every light with LEDs it's important to look at their advantages and drawbacks.

While LEDs do have a good service life, they require power supplies and drivers to operate (This is similar to HID and fluorescents requiring ballasts or high frequency generators). These are weak points in the design of LED systems and often fail long before the LED itself. They are susceptible to lighting surges and heat just like any other piece of electronics.

LEDs are monochromatic light sources by nature. To produce white light they are generally phosphor coated (similar to the design of fluorescents). Major advances are happening in the field of lamp coatings which hopefully will mean more efficacious LEDs in the near future as well as more consistant quality control. Currently, high-end white LEDs are only producing a realistic 40 lumens per watt or so. Certain pulse start metal halide systems are upwards of 100 lumens per watt and have excellent scotopic performance (very visible, nighttime illumination). Luckily for LEDs, they are very directional in nature which means that the majority of the light they create is going in the general direction that it’s aiming. The problem is no photometric system has been created yet that can accurately control the throw of an LED fixture to the extent that segmented reflectors control HID and other point light sources for site lighting applications. This reduces the overall efficiency of the lighting system and often requires more poles and fixtures to be installed.

Heat is of course another issue with LEDs. Contrary to popular belief LEDs get hot! If we stuff 50 LEDs driven at 700mA (a bit less than 3w a piece) then we need to properly design that fixture to draw the thermal energy away from the LEDs (junction point). As an LED gets hotter… its lumen output begins to go down. This makes replacement LED lamps a poor application for most fixtures. A lot of R&D goes into a good LED fixture.

I am not in any way discouraging the use of LEDs for site lighting. It is important that we explore the technology and continue to improve upon it. However the truth of the matter is LEDs are not the perfect light source for every application. Pulse start metal halide, linear and compact fluorescent and even incandescent light sources have gone up considerably in efficacy and service life in the past few years and they all have their advantages. LEDs have a ways to go before they can compete with HID and even some fluorescent technologies for certain applications such as general area lighting, flood lighting and site lighting. Currently, it would be very difficult for a municipality to prove that they can save money with LED street lights when comparing to modern HID segmented reflector fixtures.

I am beging to see the application of solar Led lighting for residential use.