by Julia Kampelman Stevenson
DC’s new street and alleyway lighting replacement project will give neighborhoods the potential to control their own light levels. In addition to reducing carbon emissions and costs, this automated system provides an opportunity to develop area-specific light plans that focus light where needed and not elsewhere. It is consequential, though, that reduction of light pollution is not its intent, and the plan – left unchecked – will maintain a light-filled night that is harmful to both humans and wildlife.
What this street lighting project does for the District
LEDs are inherently more energy efficient than the existing lights, and it is anticipated that replacing these fixtures will cut streetlight energy use in half. Reduced energy use equals fewer carbon emissions. DDOT’s projections show 38,000 tons of greenhouse gases will be eliminated each year, and an annual energy cost savings of approximately $2.5 million.
Additionally, the lights will be tied into a computerized control system with astounding remote capabilities to monitor and affect power use, allowing for fine-tuning of the lights themselves, whether altogether or street by street. It is this feature that will allow neighborhoods to advocate through their ANCs to lower the overall intensity of artificial light, thereby benefiting the well-being of us all.
Dimming the lights for health and safety
Light pollution is negatively implicated in a spectrum of mounting harms because it affects the nighttime environment for all living creatures. Life forms are dependent upon alternations of light and dark. These circadian and seasonal patterns affect physical, mental and behavioral rhythms. We are finding that artificial light causes species to respond to stimuli that are mistimed, altering the behavior of everything as the synergistic relationships found within natural ecosystems become disoriented, causing disruptions to health and reproductive systems.
Yet there are many reasons that we light up when it is dark outside. We rely on it for our personal safety in regard to both crime and road conditions. But it doesn’t always hold up under scrutiny that bright lights necessarily increase personal safety.
In the midst of Houston’s LED streetlight conversion, Rice University researchers challenged “the common perception that more streetlights lead to fewer crimes… [We find] a much muddier picture, suggest[ing] that crime is a reflection of other neighborhood contexts…. “[C]ities should be cautious in expecting direct reductions in crime with the introduction of more streetlights.”
Similarly, more light does not necessarily make us more safe when driving. The Illuminating Engineering Society of North America (IES), sets roadway lighting standards corresponding with the American Association of State Highway and Transportation Officials (AASHTO). IES states: “More light is not always correlated with better visibility, as inappropriately designed lighting can increase visibility-reducing factors such as glare.”
The color of light also has consequence. LEDs emit greater amounts of blue light, and Kelvin scales (ranging from 2,000 to 6,500) measure light’s apparent color temperature. The higher the kelvin number (k), the bluer and cooler the light. Blue-rich light is increasingly known to be harmful. Expert advice from scientists and doctors reiterates the need to go in the direction of the lowest emission of blue light possible.
In an effort to suppress this blue cast, the technology has made substantial improvements. In 2015, DDOT declared “if (LED) technology changes, we’ll change with it.” And the technology has changed. In 2018, when I wrote my first Forest Hills Connection article on the developing street lighting project, 2700 k was the lowest possible. Now, lights at 2200 k are available.
DC’s Street lighting Project specifies 2700 k LED fixtures be placed on residential streets and 3000 k are slated for arterial streets. Yet other jurisdictions – including Phoenix, Arizona; Davis, California; and Pittsfield, Massachusetts – have committed to a single low kelvin, regardless of street category or surrounding land usage.
DDOT overdoing it
National lighting standards can help guide us with our city lighting and yet DC’s new plan goes well beyond such recommendations. The light level target the agency was admittedly aiming for was the replication of current DC outdoor light levels. Wayne Savage of Sierra Club DC told a March 2021 DC Council oversight hearing that “most DC streets would still have more than twice AASHTO’s recommended [lighting] minimums, and some would have nearly three times as much.”
This is light pollution. And it is increasing exponentially. According to a 2021 study of artificial nighttime light, the quantifiable data of light emissions has grown by at least 49% since 1992. However, the true amount may be significantly higher because some wavelengths though seen by the human eye are not detectable by satellite sensors. This hidden increase could be as high as 400% in some regions of the world.
Unless we intervene, DC will be brighter than it should be or needs to be. DDOT has said it will be responsive to residents’ concerns but hasn’t explained how such a process would work. But knowing how adaptable the automated system is, we can thoughtfully consider varying criteria, such as the time of night, and the level of activity – even extinguishing lights completely in some areas at certain times – to reduce illumination levels while maintaining appropriate lights when and where needed.
Education is critical here, to understand both the hazards of over-lighting and the value of under-lighting. The International Dark-Sky Association, the recognized authority on light pollution, advocates for lighting policies that are evidence based. Its educational website has valuable resources which can ensure that decisions we make about our nighttime environment are informed and appropriate.
Where neighborhoods come in
Advisory neighborhood commissions (ANCs), our intermediaries with local government entities, are a good forum for our views. As a member of ANC 3F’s Streets and Sidewalks Committee, I co-wrote a resolution on DC’s streetlighting conversion, and this draft will be considered at the commissioners’ June 21st meeting. The intent of the resolution is to ask that DDOT put in place the operational practices and procedures that allow for continuous active engagement on this issue from the community, through our ANC. We believe that we can avoid environmentally harmful excessive light, as well as correct instances of inadequate lighting, by keeping the appropriate amount of light directed where it is needed and not elsewhere.
Perhaps we can also convince the DC Council to craft legislation that would bring the District into compliance with nationally recognized outdoor lighting principles and standards.
Research published in 2015 asserts: “…the introduction of artificial light probably represents the most drastic change human beings have made to their environment.”
If we only take the trouble, we can aim to keep artificial light from dominating the darkness and so restore the nocturnal environment.