UNIVERSITY PARK, Pa. — To support the natural feeding, mating and biological patterns of wildlife, dark skies are protected by the National Park Service. Despite the need for dark skies protection, nighttime visitors may feel safer in brighter lighting, according to a new study from researchers in the Penn State Department of Recreation, Park, and Tourism Management (RPTM).

The team led by Associate Professor Derrick Taff, doctoral student Elizabeth Himschoot and doctoral student Morgan Crump found that people were 31.6% more likely to report higher feelings of safety in white light than amber light and 81.7% more likely to report higher feelings of safety at 5.0 lux, a unit of illuminance, than 0.5 lux. For reference, 0.2 lux roughly equates to a full moon under clear skies and 5.0 lux is less than current outdoor lighting standards.

While visitors did feel more comfortable under brighter and whiter lights, this was still at levels significantly lower than current outdoor lighting practices, which suggests there can be a balance between human and wildlife needs rather than a tension point, according to the researchers. The researchers published their findings in the Journal of Environmental Psychology.

“The Natural Sounds and Night Skies Division of the National Park Service is tasked with monitoring, documenting, protecting and preserving natural light and sound,” Taff said. “Wildlife do not need the nighttime light produced by humans, as wildlife have the moon and stars. We wanted to find out how little light is needed for humans to feel safe at night.”

The researchers surveyed 156 participants at the Penn State Arboretum within a multi-mile, wooded trail course. After sunset, trained research technicians led groups of five or fewer participants through the trail system. Each group visited six different light stations that had different hues and intensities of light.

At each light station, participants completed a survey about their feelings of comfort in that lighting condition. Participants also completed functional tasks designed to explore their ability to perceive their environment. These tasks included reading signs as well as identifying shapes and colors.

The researchers said the functional tasks provided insight into whether the area was lit well enough for participants to successfully and safely execute tasks. For example, if participants could read a sign in the given lighting condition, it signified that they felt more confident in their actions and thus felt safer in that environment.

“In the presence of more light, people completed more functional tasks and felt safer because of that,” Himschoot said. “Feelings of safety need to be considered in visitor experience at national parks, balancing how low we can take human-created light to protect wildlife and ecological systems.”

The researchers said national parks need to consider both functional and psychological aspects of the visitor experience when they make decisions about lighting. Visitors should feel confident they can safely walk through a space and actually be able to safely walk through a space.

National parks can use these findings to influence their lighting infrastructure, which can include retrofitting and adapting current infrastructure to reduce the amount of light and direct it only where it is needed, the researchers said. Changes to current infrastructure could include what the researchers called “low-cost effort for high-scale impact,” such as using timers, so lights would not be active at all times of the night.

“That’s the goal in park settings — to put light only where light is needed,” Crump said. “When people are in a park-like setting, they do not need a lot of light to see the surrounding environment.”

The researchers said amber lighting could be a solution for balance between the natural dark skies and visitors’ feelings of safety, as it is not as disruptive as white light to wildlife and would still provide visitors with a light source at night to feel safe.

“We need to think about the audience of who is going to these parks at night,” Crump said. “We found these people are more willing to care about the environment and be OK with having less light, relying on flashlights or using amber lighting once they are educated about light pollution. Determining how much light is needed is a delicate line that needs to be walked.”

Peter Newman, dean of the Rubenstein School of Environment and Natural Resources at the University of Vermont and former Penn State RPTM department head; Stephanie Buckley of the State of South Dakota Game, Fish and Parks and RPTM doctoral graduate; Chang Cai of Otak, Inc.; Steve Lawson of DJ&A; and Jeremy White and Adam Beeco of the Natural Sounds and Night Skies Division of the National Park Service collaborated on this project.

The U.S. National Science Foundation Graduate Research Fellowship Program, the Suzie and Allen Martin Professorship, and the Natural Sounds and Night Skies Division of the National Park Service supported this research.