LEDs have a number of useful properties, 3 of which are useful here: directionality, specific colour and efficiency.
In addition to the inherent efficiency of LEDs, street light can be made very directional, casting light mostly along the roadway, with only a small amount down and none up. This will allow good illumination with the least light generation, further reducing power consumption and saving more money.
In addition, by using separate red, green and blue elements, the colour can be varied. By producing different colours at different times, colour vision can be helped while protecting night vison. At dawn/dusk, the lights product a blue/green light, complementing the red glow of the low sun, helping colour vison. At night, the lights generate pink light, protecting night vision. Red light on its own is too unnatural.
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I don't think LEDs have yet reached the point where they can replace general purpose illumination.
they already have led signal lights on traffic lights and some new vehicles have signal lights that are led.. it wont be that far along now...but the city and town will be looking at there bottom line when choosing. i know that the led lights for the signal lights on vehicles are 20+ dollars
To replace street lighs the City will be looking a the whole picture when it comes to cost.
-Cost of labor to replace the light source-Cost of electricity to run light source-Political promotional value-Cost of light source
This site has replacement available.https://www.ledtronics.com/ds/SLT002/default.asp#SLL002-400-2IW
My only problem with the LED trafic signals in my area is that thaey are too bright at night. I actually think they are a hazard as they are very distracting and blinding.
yeah it would take a lot of LED bulbs to create the saim illumanation, so untill a better light comes out I think were stuck!
LED's might be bright enough to see, but they aren't bright or efficient enough to be used as street lights. As far as directionality goes, a proper reflector will work with a incandescent bulb. Producing white light also saps much of the efficiency of LED's.
LED's are just breaking into the flashlight market, they're not ready to replace headlights or streetlights.
Please ignore the previous comments, as these people don't know what they are talking about. Perhaps things have changed since the comments were first posted, but they are very wrong.
LED street lights are becoming very popular, they are extremely energy efficient. A average LED street lamp has about 240 LEDs and draws about 19 watts. Far less then bulbs.
But, thats only one reason why cities are switching to them. A LED street light can last anywhere from 5 to 12 years without ANY kind of maintenance. This more then off sets the initial buying price. They are also BRIGHTER yet focus the light better onto the ground, cutting down on light pollution. The glow is also very pleasant.
I'm doing some work with a medium sized city that is trying to drop their greenhouse gas emissions by 7 percent by 2012. This is how I came across this site.
So, to recap: Can last up to 12 YEARS, VERY energy efficient, VERY bright, LOW light pollution. There really is no reason not to switch.
Please forgive me if I offended the previous comment posters, it was not my intention.
Hi Jinkguns,
Am working on a similar project and was wondering if we could share ideas on this topic and mutually benefit.
I too am working on testing and piloting both LED and Inductive Fluorescent street lights. We are running into problems with light output intensity and pattern (particularly side-to-side reach). I would be interested in any success stories where the technology passed National Standards. The last thing we want is for a victim of a car accident to find out that the street light was a new design whos performance did not meet traffic safety standards.
To Lowens, would like to compare notes on your project as I am also working on identifying opportunities to use LED for our street lights. How can we share ideas?
LED street lighting is the future because of the benefits mention above i.e very low maintance, energy efficient and environmentally friendly. I work for a company (www.gemmalighting.com) that designs and manufactures LED Street lights. Our street lights are supplied with a charging code for Un-metered supply and have already been installed at a number of locations across the U.K. including streets, carparks and airports. If you require any data for your studies please contact me at craigmiller@gemmalighting.com.
LEDs emit light in a very narrow band (i.e., a very specific colour). For this reason, colour rendering is very poor, meaning it is difficult to say a car is light blue, instead of beige, or light green. They are working on this - for instance using UV LEDs to stimulate phosphor blends that will emit a more natural "broad-spectrum" light, which would have more normal colour rendering ability. Phosphor blends are currently used in all fluorescent lights for the same purpose, creating the "cool white" or "daylight" options.
These day LED lights can come in as many shapes and sizes has any other. LED uses half as much energy as the popular CFL lights. LED are even a conventional choice for the home. I will upgrading my own home as my need for more light bulbs arises.