LEDs, Downward Lights Changing the Night in Chicago

Mary Wisnieski reports from Chicago:

…in 2017, the city started swapping out the sodium vapor lights for energy-efficient LEDs, which create a whiter radiance. When the project is complete in 2021, the city will have replaced 270,000, or 85%, of its streetlights. As of mid-December, 185,000 fixtures had been replaced, said Chicago Department of Transportation spokesman Michael Claffey.

The changes are expected to save the city $100 million over ten years, according to Wisniewski, but the city at night will never look the same again. Meanwhile, concerns about the potentially harmful public health effects of the light persist.

Included in the LED deployment program is an effort to focus streetlights downward, cutting light pollution and allowing for more visible stars at night, though the impact of that effort is still to early to evaluate, according to a source from the Adler Planetarium. No word on whether the city is motivated by the exemplary "dark-sky" movement made most famous by the city of Tucson, Arizona.