Outdoor lighting less contentious this time around

Olson showed this illustration of acceptable and unacceptable outdoor light fixture designs (new or replacement) under the proposed regulations (click to enlarge).

By Alice Waugh

In contrast to the mood at Town Meeting discussion last spring, residents at the State of the Town meeting were mostly supportive of a proposal to have new residential outdoor lighting meet certain “dark skies” requirements, with a few tweaks.

Voters rejected proposed zoning amendments in March that would have required permanent outdoor lighting fixtures to be shielded so as not to direct light above the horizontal, and imposed limits on their brightness and color temperature. At Saturday’s State of the Town meeting, Planning Board member Margaret Olson explained the reasoning behind those proposed rules and why they should not be difficult to follow.

When used at night, lights that are on the bluer end of the color spectrum (including computer screens) can disrupt the circadian rhythms of mammals because they are too much like sunlight, Olson said. Excessively bright lights are bad because “as you move from a well-lit to a dark space, the greater the contrast and the harder it is to adjust, and it gets worse as you get older,” she said. The solution is to have a larger number of less powerful lights in a warmer color spectrum, so the Planning Board is seeking limits of 3,000 degrees K. for color temperature and 900 lumens for brightness.

Another advantage of changing the zoning regulations is that it would make the site plan review process simpler and fairer, because the Planning Board would no longer have to examine and debate the lighting in each individual applicant’s plan, Olson said.

If approved, the new rules would apply only to new permanent outdoor lighting fixtures; existing light fixtures would be grandfathered, she emphasized. However, when replacing light bulbs, she encouraged homeowners to voluntarily buy bulbs with a color temperature that meets the new guidelines.

The board’s goals with the proposed rules, which will come before voters at Town Meeting again (though perhaps not in this exact form) in March, are fourfold:

• to protect the night sky by shining light only downward where it is needed, rather than skyward
• to protect wildlife by phasing out lights that mimic daylight
• having rules that are simple and easy for homeowners to understand
• being practical by encouraging residents to use lighting fixtures that are readily available and affordable while also being in compliance

Some residents, while generally supportive of the the proposed lighting restrictions, noted that the new rules would mean homeowners would need to install a large number of fixtures to compensate for the diminished brightness of each, compared to lights commonly in use now.

“A 60-watt bulb [the equivalent of 900 lumens] is not a lot. Driveway lights are about 250 watts, so you would need 10 to 20 fixtures,” said Steven Kanner, a member of the Board of Health. He suggested that the Planning Board create a mockup to give homeowners an idea of how an outdoor lighting plan should be designed to offer enough light while also complying with the rules.

Outdoor light bulbs come with a label like this to help homeowners see the brightness and color temperature when shopping (click to enlarge).

Kanner also suggested changing the color temperature limit to 3,300 degrees K. and Olson was receptive, acknowledging that the 3,000 degree figure was arbitrary and that “perhaps that level of simplicity is unnecessary.”

Buzz Constable asked that the amended zoning regulations should allow the Zoning Board of Appeals to grant exceptions, which would allow some flexibility to accommodate new lighting technology and research in the future. “We don’t want to come back and argue about color every three years,” he said.

“I can assure you that the lighting being proposed is fully adequate,” said resident Frank Clark, an astrophysicist. “We’ve become accustomed to bright lights, most of which are going up into the sky and doing nothing.”

Olson urged residents to attend Planning Board hearings this winter to learn more about these and other proposed zoning amendments and offer their input before Town Meeting.