Sustainable Outdoor Lighting

A variety of fixtures and bulbs are used for city lighting.
A variety of fixtures and bulbs are used for city lighting. NPS / Julie West

Projects Where Impacts from Outdoor Lighting Should be Considered

• Park Housing
• Roads
• Campgrounds
• Marinas
• Visitor Centers
• Parking Lots
• Regional office buildings
• Amphitheaters
• Research Centers
• Flags
• Lighthouses
• Trails
• Communication towers (cellular, television, radio)
• Docks
• Fee Collection centers
• Parking Structures
• PARK Administrative Offices
• Historic structures/homes
• Park name signs (found at entrances or visitor contact stations)
• Roadway warning signs (flashing red/yellow for pedestrian crossings, intersections, tight curves, etc.)
Shielded or full cut-off fixtures, such as this, direct all light downward
Fully Shielded/Cut Off Fixture: direct all light downward. NPS Photo

SUSTAINABLE OUTDOOR LIGHTING (Park Friendly Lighting):

•Improves energy efficiency
•Reduces operational and cyclic maintenance costs
•Reduces carbon footprint
•Enhances architectural aesthetics
•Maintains historic authenticity
•Enhances Wilderness Character
•Minimizes impacts to wildlife and visitors
•Preserves night skies
•Provides for basic human safety
•Enhances opportunities for local economic growth through as tronomybased tourism

SUSTAINABLE OUTDOOR LIGHTING SPECIFICATIONS

In order to recognize the benefits of sustainable outdoor lighting highlighted above, the following Lighting specifications should be followed; however, LED lighting technology is improving and evolving very quickly. We will try to keep up with these changes.

1. NO LIGHTING AT ALL – the first question in considering what type of outdoor lighting is appropriate for an area or structure/facility in a national park is whether there even needs to be a light at all. In many cases, reflective tape of other reflective surfaces can be used instead (this is a good option for roadway, parking lots, parking garages and trails where people will have headlamps, flashlights, and cell phones lights).

2. LEDs in Warm Colors – 2700 Kelvin. Use energy efficient LEDs that have a warm color hue; e.g., yellow, amber; NOT blue or white (note: the most highly efficient LEDs are not preferable because they have a lot of blue which creates more glare and blind spots, has potential health effects, and isn’t considered wildlife friendly).

3. Recessed and Fully Shielded – Hockey puck style lights that can be inserted under a soffit or some other architectural feature are very useful; avoid globes or diffusers that hang below the light fixture; use “full cut off” shielding – allows excess light to be directed downward and not upward.

4. No Upward Facing Lights – Outdoor lighting should be designed and installed to be downward facing (e.g., park signs and flags often have upward facing lighting that can be easily made to point downward.). Avoid lights that directed laterally as well.


5. Lighting Fixtures That Include or Can Accommodate Timers, Motion Detectors, Hue Adapters, and Dimmers – these adaptive technologies can increase energy efficiency and reduce impacts to park natural and cultural resources substantially. Further, they can enhance visitor health and safety.

6. Lowest Lumens Possible – Lumens are the unit of measurement used to specify the intensity or brightness of LED bulbs. The number of lumens needed to safely light an area is usually much lower than most people think, especially outdoors. LEDs are also much brighter and more energy efficient than other types of lighting so you can go with a much lower wattage LED and still have the same level of brightness. For example, a 250-watt incandescent bulb has the same lumens as a 30-watt LED bulb. Field adjustable wattage selectors are also a good option for reducing impacts, increasing cost savings, and extending product life.


7. Proper Installation - Lights should be installed with proper angle and height as designed. Another benefit of using LEDs for outdoor lighting is that LED luminaires allow for very specific control of the beam spread. The size of the lighted area will change depending on the height of the fixture or pole so the beam spread should be accounted for during installation to avoid lighting a greater area than needed. For example, a type I beam spread is typically used for roads while Type V may be more appropriate for a parking lot. Proper installation and spread angle can also reduce the number of lights needed in general.

EFFECTS OF LIGHT POLLUTION IN NATIONAL PARKS

Night Skies

National parks are some of the best places in America to see the starry night sky. Staring at the spectacular array of stars in the night sky with the light band of the Milky Way streaking overhead is a quintessential experience for many national park visitors. Astronomy based activities are among the most popular visitor programs offered in parks, and night sky festivals often attract thousands of participants. However, natural lightscapes in many national parks have been diminished by light pollution, which occurs in two main forms, sky glow and direct glare, most of which results from poorly designed outdoor lighting.
In addition to visitor experience, good lighting conditions are important for wildlife habitat, protecting cultural resources, enhancing wilderness character, wayfinding and avoiding human wildlife conflicts. The National Park Service is charged with protecting night skies along with other park resources. To prevent the loss of dark conditions and of natural night skies, NPS advances science-based principles of sustainable outdoor lighting.


Wildlife and Other Natural Resources

Light pollution can affect wildlife interactions and other vital ecological processes including predator/prey relationships, reproduction, navigation and migration. Nearly half the species on Earth are nocturnal. The absence of light is often a key element of their habitat. Even in areas where the overall sky is affected by skyglow, the more localized glare can affect navigation and habitat selection for wildlife

Cultural Resources

Throughout history the night sky has inspired people from all cultures. From the cosmic myths of ancient Greece, to the architectural alignments of ancient monuments at Chaco Canyon and Chichén Itzá, to the oceanic navigation methods of Polynesian voyagers - the celestial tapestry of stars, planets, galaxies, and other celestial features has found its way into stories, songs, rituals and traditions around the world. Night skies are also important for the current generation of park visitors and a starry sky often provides an important backdrop to connect visitors to experiences at many historical and cultural sites – such as contemplating the lives of western settlers at Homestead National Monument, the underground railroad at Harriet Tubman National Historical Park or understanding the ancient ruins and solar markers at Chaco Culture National Historical Park.

Cultural/Historical Authenticity

Many national parks may have historical or cultural sites where nighttime lighting is an intrinsic part of the park. The grandeur of a memorial or the magnitude of a historical event can be enhanced by nighttime lighting. Nighttime lighting may be significant to the visitor experience or required to effectively manage cultural resources. Careful consideration of such lighting should include how it affects resources and values in the park and whether the timing, amount and direction of the lighting are appropriate.

Wilderness Character

Preserving a dark night sky and reducing light pollution is critical for effective wilderness management. Lighting can affect wilderness qualities of solitude, naturalness, untrammeled and undeveloped character. Artificial light is often the most common and pervasive human influence on the primeval character of wilderness.

Human Health, Public Safety, and Visitor Experience

The nighttime environment plays an integral role in human health and physiology. Dark nights (and bright days) are key in keeping our circadian rhythm in sync. It is well documented that without the restorative power of consistent restful sleep, serious health consequences can arise.

Artificial light can impact visitors in two ways: direct glare from light fixtures can affect vision and nighttime recreation experiences; and sky glow from collective sources of artificial light scattered in the atmosphere can obscure views of the night sky. Both aspects of artificial light can unnaturally illuminate the ground and diminish visitors’ ability to dark adapt their vision, cause blind spots, and create potential safety issues as well. (e.g., wildlife/visitor conflict).

References

Artificial Night Lighting and Protected Lands: Ecological Effects and Management Approaches (Revised August 2017). Natural Resource Report NPS/NRSS/NSNS/NRR—2017/1493

Dan Duriscoe, "Preserving Pristine Night Skies in National Parks and the Wilderness Ethic," The George Wright Forum, 18:4, 2001.[64 KB PDF].

5 outdoor lighting tips from IES/IDA: Useful, Targeted, Low Light Levels, Controlled, and Color

IES/IDA graphic

More Outdoor Lighting Tips from our Partners at the Illuminating Engineering Society and International Dark Sky Association

Last updated: March 4, 2022