Dialight A streetlight with light-emitting diodes can be dimmed to take account of dusky conditions.The light-emitting diodes that are now common in traffic lights seem poised to move into more streetlights — and to get smarter.
Light-emitting diodes, known as LEDs, produce three or four times more light per watt of electricity than standard incandescent lamps do. They do not “burn out,” although they may lose brightness over time. Since traffic signals are always on, and maintaining them requires getting up many feet over the pavement of an intersection, they have been excellent candidates for new technology.
The Dialight Corporation, of Farmingdale, N.J., a subsidiary of a British company, says it has about one-third of the United States market for LED traffic signals, which now make up about 70 percent of all traffic signals. It also specializes in the lights that blink on top of radio towers and other tall objects where replacement is arduous and expensive.
But Dialight has its eye on another target, street lamps, and is trying some out in Edinburgh and in Pittsburgh.
An LED street lamp does not produce much more light per watt than the incumbent technologies. But while the conventional lamps shine in all directions, the LED light is built to shine in one direction. So a smaller
lamp can be used to light the area where light is really needed. And LEDs can be dimmed to take account of dusky conditions or nighttime hours when less illumination is acceptable.
Roy Burton, the company chief executive, said that such lights now sell for $600 or $700 each, at least double the price of a conventional light. Relying simply on energy savings to pay back the extra cost would take six or seven years, he said, which “is not a particularly great investment.”
But a “smarter” light that was easy to control remotely and reported back on its condition would be worth investing in, he said.
So the company is developing a cluster of lights that communicate wirelessly with one master light equipped with cellphone technology. A light would report back on its condition: “It would say, ‘Yes, I’m good, things are going well,’ or ‘Things are not going well,’ or ‘I’m turned off,’ ” Mr. Burton said. That should reduce the number of crews out looking for failed lights, he added.
But cities might pick them for a nonfinancial reason, he said: LED’s look better. The difference is obvious to anybody with an LED flashlight.
“It’s a nice, white light, not all yellow-y,’’ he said.
An earlier version of this post described sulfur lamps as a dominant streetlight technology. They are not in common use.