> Not sure how they're going to achieve that. LEDs produce 37 to 120 lumens/watt, HPS and LPS produce 50 to 160 lumens/watt. The sodium lamps lose out only beca

> Not sure how they're going to achieve that. LEDs produce 37 to 120 lumens/watt, HPS and LPS produce 50 to 160 lumens/watt. The sodium lamps lose out only because they are omnidirectional and a mirror is required to aim their light down, so some of the light is blocked by the lamp itself. But overall LEDs don't save 50%. I did a quick search and found their RFI [1]. They are reducing electricity consumption by 50% because they are replacing 40+ year old light fixtures that have 70+ year old wiring: > In the 1950s, the City installed new lighting infrastructure citywide; utilizing mercury vapor lamps. In the 1970s, the City performed a system-wide lighting upgrade; replacing the mercury vapor fixtures with high-pressure sodium fixtures. This project was only a lamp head upgrade; the City retained the 1950s era electrical poles, wiring, and infrastructure. Over the years as underground wiring has failed, City crews have often replaced underground wiring with aerial wiring. In 2009, using available federal funding, the City replaced high-pressure sodium streetlight fixtures with more energy efficient ceramic metal halide fixtures along Western Avenue and Lake Shore Drive. That fixture replacement undertaking did not include upgrading the electrical infrastructure. [1] http://chicagoinfrastructure.org/wp-content/uploads/2014/10/ChicagoSmartLightingRFI-Final_20150917.pdf http://chicagoinfrastructure.org/wp-content/uploads/2014/10/...