Bright LEDs can spell the end of dark skies.

NASA

The specifications in the current proposal provide a starting point for a plan that includes a 3,000 K color temperature cut in line with Pittsburgh’s dark sky ordinance passed last fall. However, Martinez says this is the maximum, and when looking for advisors, they consider those who demonstrate knowledge of dark skies. The city is also considering — budget and infrastructure permitting — a “networked light management system” that would monitor light levels and detect when there are outages, a type of “smart” lighting.

Martinez said there will be citywide engagement and updates on the situation as they reach milestones. “We’re in the evaluation phase right now,” she said, adding that the next step is to authorize a new contract. She said there is some “high interest in street lighting” and she’s anxious to see the project come to fruition: “Just because things seem quiet doesn’t mean work hasn’t been done.”

While they’re not currently meeting with light pollution experts, Martinez said the ones he met during the final proposal round — Stephen Quick and CMU’s Diane Turnschek — were “instrumental” in getting the dark skies rule passed.

In recent months, Zielinska-Dabkowska’s “baby” was the first responsible outdoor light at the Night Conference, an international gathering of more than 300 lighting experts and light pollution researchers held in May. Barentin was among the speakers. “It’s a sign that it’s not just a research topic, but something that’s of great interest to practitioners,” he said of the conference.

There is still much work to be done. IDA recently summarized the current state of light pollution research. The 18-page report details knowledge gaps in various areas, including the effectiveness of general government policies on light pollution. Another 2020 study found that only 13 percent of Tucson’s light pollution comes from outside the city’s street lights. It’s unclear what the rest is, but Barentin suspects the next biggest source in the United States and Europe is commercial lighting, such as flashing LED signs and parking lights.

Working with companies to reduce light emissions can be challenging, said Clayton Trevillian, Tucson’s chief construction officer. “If there’s a light source inside the building, it’s technically not regulated by the exterior lighting code, even if it emits light to the outside,” Trevillion says. In some cases, he said, around the city’s restrictions, businesses have blocked lighted signs inside buildings but aimed them outside.

Light pollution experts generally say that there is no conclusive evidence that more light leads to greater safety.

For cities trying to implement lighting ordinances, Trevillian says, the biggest roadblocks they face are “irrelevant” arguments, specifically that reducing the brightness of outdoor lighting reduces advertising revenue and makes the city more vulnerable to crime. He said the key to successful enforcement of the Dark Skies Act is educating the public and not giving in to those seeking exceptions or exploiting loopholes.

Light pollution experts generally say that there is no conclusive evidence that more light leads to greater safety. For example, the city of Tucson has seen no increase in traffic accidents or crime since dimming its street lights and restricting outdoor lighting in 2017. Last year, University of Pennsylvania researchers analyzed crime rates with 300,000 street light outages. A period of eight years. They concluded that there was “little evidence” of any effect on crime rates on affected streets—in fact, criminals sought better-lit neighborhood streets. Barentin said there is some evidence that “strategically placed lighting” can help reduce traffic collisions. “Beyond that, things get destroyed very quickly,” he says.