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Cities around the country are turning to light-emitting diodes, or LEDs, for their street lights. These bulbs use less energy, last longer and are smaller than traditional lights and they save money. But there's a problem with some LEDs. Grace Hood of Colorado Public Radio reports.
GRACE HOOD, BYLINE: The small southwestern Colorado city of Ouray is known for hiking and ice climbing. In 2009, Ouray's city administrator Patrick Rondinelli and others jumped at the chance to install LED streetlights. It became the first in the state to make the move.
PATRICK RONDINELLI: In Ouray, we're very fortunate. We can actually still see the Milky Way where, you know, you get to Denver, you can't see that anymore.
HOOD: LEDs can reduce light pollution if properly directed toward the ground. Ouray's street light bill is one-third compared to what it used to be. Across the country, LEDs make up about 10 percent of outdoor lighting. Since energy savings can be significant, many cities are eyeing a change. But this June, the American Medical Association issued guidelines saying some LEDs, like Ouray's, emit a color that can disturb people's sleep patterns.
MARIO MOTTA: The problem is some of the early LEDs that were produced have very high intensity blue.
HOOD: Dr. Mario Motta serves on the AMA's Council on Science & Public Health. He says that blue light is linked to a decrease in melatonin production, which means it could be upsetting people's sleep. When adopting new LEDs, Motta says cities should opt for whiter, warmer lights.
MOTTA: There is the same cost to produce, the same longevity and the same energy savings. So given everything is equivalent, there's absolutely no reason to put in bad lighting. You can put in good lighting.
HOOD: Some lighting experts and trade groups have criticized the AMA guidance for pushing a single solution for all cities and streets. But most experts agree that LEDs will eventually replace what cities have now. Lighting designer Nancy Clanton says LED technology is becoming more and more advanced.
NANCY CLANTON: You can do whatever you want with this.
HOOD: Clanton has helped plan LEDs for cities including San Diego and Anchorage. She says each place has unique needs. In San Jose, she worked to install smarter technology that allows them to dim street lights.
CLANTON: Right before the bars close, they increase the lighting level so that everyone knows it's time to go home. And then they decrease it back down again.
HOOD: This dimming technology exists on a new $2 million project Denver's installing on its iconic 16th Street Mall. Denver Public Works spokeswoman Heather Burke says, for the most part, the fixtures look the same. But the light will be distributed more evenly.
HEATHER BURKE: It's going to be a more white, brighter light. And it's going to shine more evenly on the sidewalks here.
HOOD: And that's good for public safety. These lights also meet the new AMA recommendations. Back in Ouray, city administrator Patrick Rondinelli says he has no qualms about the city's transition to LEDs. Even though they're too blue and they don't meet the AMA's guidance, he's happy with the change. We end our tour in front of city hall.
This summer, he converted lights on the building to use LEDs, save money and reduce light pollution.
RONDINELLI: To put a new light in and then not have to worry about it for the next 10 years is a great thing.
HOOD: So despite some of the, you know, bumps in the road, it sounds like you're sold on LEDs.
RONDINELLI: Oh, absolutely. Yeah, I mean, we've had some lessons learned along the ways but there's no regrets.
HOOD: Ouray's original LEDs cost $60,000. And the next generation won't come cheap for this small town with a limited budget. But Rondinelli knows the longer he waits, the better the technology will become. For NPR News, I'm Grace Hood in Ouray, Colo. Transcript provided by NPR, Copyright NPR.