By admin
Drivers and cyclists traveling along Frederiksborgvej in the Copenhagen suburb of Gladsaxe have recently encountered a striking change in the nightscape: a stretch of road now illuminated not by familiar white streetlights, but by an eerie red glow.
The transformation began in early February 2026, when the municipality installed red-spectrum LED lights along a roughly 700-meter section of roadway and the adjoining Farum cycle superhighway. The unusual lighting has turned the busy corridor into a crimson passageway—an aesthetic shift driven not by style, but by wildlife protection.
Local officials say the project is designed to reduce the impact of artificial lighting on bats, which use the area as a key feeding and navigation route.
Species such as the common pipistrelle and the brown long-eared bat are highly sensitive to artificial light. Traditional white LEDs, particularly those rich in blue wavelengths, can disorient nocturnal mammals and alter the behavior of insects they rely on for food. In some cases, bright lighting can effectively create barriers that bats avoid crossing.
Red light, by contrast, emits longer wavelengths that bats largely perceive as darkness. The result is a compromise: motorists and cyclists retain enough illumination to navigate safely, while the surrounding habitat remains usable for the animals that depend on it.
The red glow also serves another purpose. Officials hope it will act as a visual signal that the road passes through a sensitive natural corridor.
Philip Jelvard, a lighting designer involved in the project through the firm Light Bureau, emphasized that the lighting was intended to serve both practical and symbolic roles.
“Overall, we hope that everyone welcomes the new lighting and that the red light not only has functional value, but also symbolic value. The red light should make passers-by aware that this is a special natural area that we want to protect.”
Though unusual to the human eye, the lighting still provides sufficient visibility for drivers and cyclists to detect obstacles and maintain safe travel along the route, officials say. The primary adjustment required is simply acclimating to the different color spectrum.
The project is part of a broader experiment in sustainable urban lighting. Gladsaxe’s initiative operates within the EU-supported Lighting Metropolis – Green Mobility program, which brings together Danish and Swedish municipalities to test environmentally sensitive illumination technologies.
The effort reflects a growing challenge for modern cities: balancing infrastructure needs with ecological preservation. Artificial lighting, once considered a purely technical matter, is increasingly recognized as a significant factor in habitat disruption, particularly for nocturnal wildlife.
Researchers have long warned that light pollution can interfere with migration patterns, feeding behavior, and breeding cycles for a wide range of species—from birds to insects to mammals.
Urban planners are now exploring alternatives such as directional lighting, dimming schedules, and spectrum adjustments to reduce those impacts without compromising safety.
Gladsaxe’s red-light corridor represents one such approach. By altering the color spectrum rather than eliminating lighting altogether, the municipality hopes to maintain modern infrastructure while protecting biodiversity.
The experiment also comes at a moment of accelerating urban growth. More than half the world’s population now lives in cities, and projections suggest that figure could approach 70 percent by 2050.
As urban areas expand, the pressure on surrounding ecosystems grows with them. The challenge for planners is finding ways to reduce environmental disruption without halting development.
