By James W. Sweeney, Mayor, Village of Cambridge, New York
There are nights in Cambridge when the stars still show themselves clearly. Nights when Orion and the Big Dipper hang over the rooftops and the air carries the calm, dark clarity that belongs to this part of the world.
And then there are other nights when the sky glows white and restless, when hard light flattens shadows and turns the horizon into haze.
The difference is not always weather. Sometimes, it is the way we light our homes.
Outdoor lighting has changed dramatically in the LED era. LEDs are one of the great energy-saving technologies of our time: they use far less electricity than traditional incandescent bulbs, last much longer, and make reliable exterior lighting inexpensive.
But those same advantages can make it easy to use more light than we need. High-output floodlights and cool-white “daylight” bulbs are now inexpensive to buy and inexpensive to leave on. A fixture intended to illuminate a doorway or driveway can instead shine across a fence, into a neighboring yard, through a bedroom window, or upward into the night sky.
This is not an argument against outdoor lighting, and it is not primarily about enforcement. It is about neighborliness.
Light, like sound, does not necessarily stop at a property line.
The most considerate lighting does its job on our own property without unnecessarily becoming part of someone else’s.
Good Lighting Is Not Simply More Lighting
A bright yard can feel safer, but more light is not always better visibility. Poorly aimed or overly intense lighting can create glare, reduce useful contrast, and make it harder for our eyes to see into darker areas beyond the illuminated space.
The American Medical Association has recommended that outdoor LED lighting be properly shielded, that blue-rich lighting be minimized, and that communities favor outdoor lighting with a color temperature of 3000 K or lower. It also encourages dimming during periods when full illumination is unnecessary.
The principle is straightforward: use enough light for the task, put it where it is needed, and avoid sending it where it is not.
That approach can improve visibility while reducing glare, wasted light, and intrusion onto neighboring properties.
Why Darkness Matters
The effects of artificial light at night extend beyond what we can see from our own porch.
For people, darkness is part of the environmental signal that helps regulate the body's sleep-wake cycle. Blue-rich nighttime light can affect circadian signaling and melatonin, which is one reason warmer, lower-intensity lighting is generally better suited to nighttime environments.
For some people, unwanted light is more than an annoyance. Light sensitivity is common during migraine, and bright or flickering light can cause substantial discomfort for susceptible individuals. A small proportion of people with epilepsy also have photosensitive epilepsy, in which certain flashing lights or visual patterns can trigger seizures. Considerate lighting is therefore also an accessibility issue: shielding, sensible intensity, and steady illumination can make shared nighttime environments more comfortable for more people.
Wildlife depends on darkness as well. Many migratory birds travel at night, and artificial light can draw them toward developed areas, disrupt navigation, and increase their risk of building and window collisions. Cornell researchers note that turning off unnecessary nighttime lighting is one simple way households can reduce that risk.
Insects and other nocturnal species also evolved around a predictable alternation of daylight and darkness. When we illuminate the night continuously, we change an environmental condition on which entire ecosystems depend.
Restoring some darkness is not about austerity. It is about proportion: using enough light to live safely and comfortably without treating darkness itself as a problem that must be eliminated.
Cambridge Has Already Defined the Principle
Cambridge has been thinking about good lighting for a long time.
The Village’s 2005 Design Guidelines describe “good lighting” as lighting that performs its intended task without over-lighting, uses shielding to keep illumination in the intended area, minimizes effects on neighboring property, and considers the color and quality of the light itself.
From the Village of Cambridge Design Guidelines (2005): examples of poor and good lighting fixtures.
For the types of development addressed by those guidelines, Cambridge also calls for pedestrian-scale lighting of 10 to 12 feet, limits area lighting to 18 feet or the building height, whichever is lower, and specifies shielding to prevent glare toward neighboring properties, streets, and the sky. The guidelines also establish a 0.5-footcandle limit for illumination extending beyond a property boundary.
Those guidelines were developed as a design and educational tool rather than as a handbook for every porch light in the Village. But the underlying principle translates easily to our homes:
Illuminate what needs to be illuminated. Shield the source. Keep the light where it belongs.
Simple Choices That Make a Difference
Most households can improve outdoor lighting without sacrificing convenience or security.
Choose warm-white LEDs, generally around 2700–3000 K, rather than cool “daylight” bulbs in the 5000–6500 K range.
Aim fixtures downward and toward the area that actually needs illumination.
Use shields or fully shielded fixtures so the bulb itself is not glaring into neighboring properties or the sky.
Use motion sensors, timers, or dimmers so full lighting is present when needed rather than throughout the night.
Choose the lowest useful light output for the task instead of automatically selecting the brightest bulb or fixture available.
When buying a new fixture, consider products designed according to recognized dark-sky lighting principles.
The aim is not darkness everywhere. It is useful light where useful light belongs.
A Broader Conversation
Cambridge is not alone in considering these questions.
New York lawmakers have introduced legislation during the 2025–2026 session that would establish broader standards for outdoor nighttime lighting. Assembly Bill A4615, for example, would require shielding for many outdoor fixtures while providing a number of exemptions; related dark-sky legislation has also been introduced in the Senate. The measures remain under legislative consideration and have not become statewide law.
Whatever happens in Albany, however, Cambridge does not need to wait for a statewide mandate to practice good lighting.
A Village Vision
Our own Design Guidelines already point toward the larger idea: good lighting reveals what we need to see without creating unnecessary glare or intrusion.
That principle belongs just as naturally on a porch or garage as it does in a development plan.
When a neighbor adjusts a floodlight, adds a shield, installs a motion sensor, or chooses a warmer bulb, the act may seem small. But it expresses something larger about the kind of village we want to be.
We live close enough that what happens on one property can affect the next. Our trees cross boundaries. Our sounds carry. So does our light.
Consideration begins with noticing that fact.
Let the night be night. Let light serve its purpose without becoming a presence of its own. And let Cambridge remain a place where a clear, quiet sky can still belong to everyone.
Sources & Further Reading
American Medical Association. Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting, 2016.
DarkSky International. Guidance on responsible outdoor lighting and approved lighting products.
Cornell Lab of Ornithology. Resources on artificial light at night, bird migration, and window collisions.
Village of Cambridge. Design Guidelines, Section 2: Site Design, 2005.
New York State Legislature. Dark Skies Protection Act, 2025–2026 legislative session.
Falchi et al. “The New World Atlas of Artificial Night Sky Brightness.” Science Advances, 2016.
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