Light Emitting Diode Technology...
Even Traffic Lights Can Save Energy...and Tax Dollars
Light-Emitting Diode, or LED, traffic signals can be real energy and dollar savers.
According to ENERGY STAR's Traffic Signals website, LED traffic signals have a “significant energy savings potential,” possibly saving “...2.7 billion kilowatthours a year nationwide.”
LED traffic signals have several advantages over traditional incandescent type of traffic signals. LED signals enjoy a lifespan ten times longer, resulting in lower maintenance and replacement costs and they are low wattage — a 135 watt red incandescent traffic light is replaced by a 10 watt LED. These advantages translate into dramatically reduced energy costs. Additionally, an incandescent red traffic light burns out at all at once which can cause serious problems, but the comparable LED consists of a hundred light emitting diodes that burn out one at a time so the red LED traffic light is still very functional until the LED is replaced.
This new technology is beginning to make headway in the marketplace. Rensselaer Polytechnic Institute's Lighting Research Center Light-Emiting Diodes website is the comprehensive website on LED traffic signals. The web site has several success stories on LED traffic signal installations as well as a report on Luminous Intensity for Traffic Signals: A Scientific Basis for Performance Specifications. The web site also includes a discussion of energy and environmental issues.
Regarding technical performance of LED traffic signals and their ability to perform safely, the Institute of Transportation Engineers has developed an Interim Purchase Specification for LED Vehicle Traffic Control Signal Modules. You can contact the Institute by phone at 202-289-0222, ext. 130. Oregon and California both have specifications regarding LED traffic signal modules. The City of Portland has published their LED Traffic Signal Success Story.
The August 4, 2004 issue of EERE Network News reports on four cities which have replaced or are in the process of replacing incandescent street lighting with LEDs.