TransCore's Karl Korhonen (above) and Richard Niell replace a street light with a new LED light fixture August 1, 2011 in Las Vegas, Nevada. The new energy-efficient fixtures are expected to reduce the city's annual electricity use by eight million kilowatt hours, saving about USD $400,000. The city estimates the LEDs will last about 15 years, nine years longer than the current lights. Funding for the project comes from federal energy conservation bonds and an American Recovery & Reinvestment Act grant. The city plans to replace all of its 50,000 streetlights after more funding is secured. (Photo by Ethan Miller/Getty Images)

Old street lights are stacked on a truck after being removed and replaced with new LED light fixtures August 1, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)