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The difference between the brighter new streetlights and the older ones can clearly be seen in this shot from Laurel Street. (Photo by Chip Scheuer)

The difference between the brighter new streetlights and the older ones can clearly be seen in this shot from Laurel Street. (Photo by Chip Scheuer)

On a wooden fence surrounding a Live Oak neighborhood, residents tacked up hand-written posters: “Move the Target sign. It’s too bright!” and “You have neighbors!” Seventy residents signed an online petition calling for Target to turn off or dim its large bulls-eye sign, which faces a residential area.

“Would LOVE to get to sleep at night without the BRIGHT RED LIGHT shining through my bedroom window. Really too old for a night light,” wrote resident Lynette Whaley on the petition. Another resident, John Silva, boarded his bedroom window with plywood so the light wouldn’t shine in. At a community meeting held by Supervisor John Leopold last week, Silva played a 90-second video he had created with footage of the sign scored by Sting’s “Roxanne.” The 25 residents in attendance nodded in solidarity.

While 25 Live Oak residents seeing red may not seem like much, it is just one example of how light can affect a community. 

The city of Santa Cruz has about 3,000 street lights, over half of which have been converted to light-emitting diode (LED) since August of 2011. And it has been a long time in the making. Santa Cruz Director of Public Works Mark Dettle says the city began thinking about LED street lights two or three years ago, and watched other cities to see how the technology developed.

With a lifespan of 10 years compared to just two years on the city’s existing bulbs, Dettle expects the LED lights will save Santa Cruz $260,000 in maintenance costs over that time. A longer lifespan also means less landfill waste. Plus, LED lights don’t contain hazardous waste, so they can be completely recycled. Dettle says the city’s main impetus for switching to LED lights was a lower cost and a reduced carbon footprint.

Aesthetics and public safety were also taken into account, he says. LED lights emit a crisp white color compared to the previous streetlights, which appear more yellow.

“It’s more efficient light,” says Dettle, who believes brighter, whiter light makes pedestrians feel safer and provides a more accurate portrayal of surroundings. “Now, when you see the colors of cars and other things at night, they’re truer to what they look like during the daytime,” he adds. “If you have to identify a vehicle you can tell the true color of the vehicle much easier now.”

Beyond just a feeling of safety, certain types of public lighting can actually save lives. For example, in 2000, the city of Glasgow, Scotland introduced blue street lighting in certain neighborhoods. Whether because blue is calming, or because it is a color commonly associated with the police, it was credited with a drop in crime in those areas. A few years later, a train station in Yokohama, Japan installed blue lighting on railroad platforms to curb the number of people committing suicide by jumping in front of trains.

 

Dark Side of Lights

The effects of public lighting on humans aren’t all positive, though. “Bright white light suppresses melatonin, the hormone that regulates tumors,” reported researchers from Carnegie Mellon University’s Remaking Cities Institute in a recent report. “Blue light wavelengths are to blame, because they ‘reset’ the circadian clocks of humans…This might account for the significantly higher rates (30-60%) of breast and colorectal cancer in night shift workers.”

Those wavelengths are also one reason not everyone is happy with the city’s switch to LED.

“The blue-white LED lights are too bright. If a less blue LED color could be used, the lights would be much easier on the eyes,” says Santa Cruz resident Mark Buxbaum, an environmentalist and amateur astronomer whose license plate frame reads, “For Starry Nights Dim Outside Lights!”

And the impact of public lighting reaches far beyond the lives of us mere mortals. Jack Sales, California chapter leader of the International Dark-Sky Association, says light disrupts nocturnal animals and can affect their foraging, mating and navigation, causing some species “not to be as robust as they might normally be. 

City lights also limit astronomy, both in the backyard and professional sense, says Sales. “Public lighting today is the biggest threat to astronomy and the dark night sky,” he says, adding that he has more hope for an LED-lit future since most LED street lights are more directional and efficient, while the alternative high-pressure sodium lights tend to let unnecessary amounts of light escape from the sides and tops of lamps.

Still, Sales says we waste thousands of gigawatts of light each year in California. “From an educational standpoint, we’re destroying a free resource.” When it comes to astronomical exploration, astronomers are “restricted in the methods they can use for finding extraterrestrial planets and stars. They can’t do direct observing like they used to do.”

When asked if the extreme brightness of earth makes it easier for extraterrestrials to find us instead, Sales laughs. “Well, that could be. The thing is, light travels essentially forever. That light that comes out of an outdoor lamp can travel forever… Photons keep going.”

However, our future alien overlords will have to look elsewhere for their beacon to the Capitola Mall—at last week’s community meeting Target agreed to turn off its sign. 

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  • http://www.santacruz.com/news/2013/01/15/led_streetlights_come_to_santa_cruz Paul Preto

    Jack Sales correctly points out that proper shielding of the LED lights would aim the light at the ground, not in directions where it is not wanted. The city should have considered such shielding, especially since UC Santa Cruz is home of one of the most prestigious astronomy departments in the world.  Furthermore, as anyone who has purchased the new LED Christmas lights knows, a colored mantle in front of the LED can change the observed color to any shade desired. The idea that bright white light is required for public safety, while seemingly intuitive, is just not true. This has been debunked by several controlled studies.

  • http://www.arizonasmilecenter.com Rix Allison

    I hate it when I’m driving at night and meet another car with bright LED lights. They blind me every single time. Argh!