Light-Emitting Diodes, or LEDs as they're better known, are replacing red signals in some traffic lights around the US. The LEDs use up to 90% less electricity than incandescent bulbs and can last around 6 times as long (7-10 years instead of 1-1.5 years).
While LEDs make more environmental and economic sense than standard light bulbs, they are significantly more expensive initially (red LEDs are $120-140, green LEDs can be $275, and bulbs are $2.50), especially in the short-term perspective most states and cities take for budgeting. Plus, red is the easiest color for LEDs to produce, which makes a fully-LED-driven traffic light much more difficult and expensive to implement.
LEDs are already replacing bulbs in automobiles, and advocates hope LEDs will be as omnipresent in our lives as normal bulbs are once a cheap and easy way to produce white light from LEDs is found.
For more information, please read this excellent article at digitalMASS.
I think this is really cool. I've been a huge fan of LEDs ever since finding out when I was in 5th grade that they were what was creating the light in my Coleco Head-to-Head and Mattel handheld football games :)
I love the concept of replacing bulbs with LEDs because it's cool to see “new” technology (even though LEDs are about 40 years old) affecting new parts of our everyday lives. The energy savings alone is worth the change, and maintenance hassles would be significantly reduced. Replacing LEDs might not currently be as easy as changing bulbs, but I'm sure that aspect would be improved if the technology became more widespread. The article also says that LEDs light up more quickly than bulbs; not a lot, but enough that your eye would be able to tell the difference. We've been using Edison's bulbs for quite a while now (I know he didn't invent them, he just perfected the design), and fluorescent has never really been as widely accepted, so maybe it's time to push this obviously more efficient LED technology so that the price will drop.
The article is REALLY worth the read … two of the facts that I found amazing are that the U.S.'s 3.1 million traffic lights use up at least $250 million per year in electricity (!!) and that a yellow (or amber) light loses 80% of its light when it gets filtered through the glass. The article also talks about other areas of our lives where LEDs could become prevalent, including home lighting. Reading it actually made me excited about what LEDs could do to make my life cooler :)