New York City is transitioning its 250,000 street lights to energy-efficient LEDs in an upgrade that should be completed by 2017. CBS reports that Mayor Michael Bloomberg announced the time frame today, noting that the upgraded lights will save city taxpayers around $14 million a year once the transition is complete. The savings are two-fold: LEDs consume less power than their high-pressure sodium counterparts, resulting in around $6 million in savings, and they also have a much longer lifespan, lasting up to 20 years. Current street lights last an average of just six years, Bloomberg said.

The project has been a long time in the making. New York City has been testing LED lights for a number of years — they're currently used in areas of Central Park and on the "necklace" lights on the cables of East River bridges, to name just a few locales — with the city's Department of Transportation partnering with the Climate Group and the US Department of Energy in 2009 for several studies on the efficacy of the technology. This new announcement comes as more and more cities have started adopting LED lights; last year Los Angeles completed its own massive LED project, retrofitting 141,089 street lights with LED bulbs. New York's LED project is expected to be the largest of its kind in the United States when completed.

"With roughly a quarter-million street lights in our city, upgrading to more energy efficient lights is a large and necessary feat," Mayor Bloomberg said in a statement. "It will save taxpayers millions of dollars, move us closer to achieving our ambitious sustainability goals, and help us to continue reducing city government's day-to-day costs and improving its operations."