Denmark is turning streetlights red in Copenhagen suburb: THIS reason will shock you

Denmark is replacing white lamps with red lighting along selected roads in a suburb near Copenhagen to reduce harm to wildlife while keeping streets usable for people. The experiment has also attracted attention beyond Denmark, to light streets without overwhelming the environments around them.

The project is being carried out in Gladsaxe, a suburb on the edge of Copenhagen, where conventional streetlights along parts of Frederiksborgvej near Skovbrynet are being replaced with red-hued lighting. A statement from the Gladsaxe municipality said the area is home to a local bat colony, as per the report in TOI.

Instead of switching the lights off completely, officials opted for a colour designed to change how artificial light affects wildlife. The modification is noticeable only at night and only on selected parts of the road.

Red light is likely to be less disruptive

Bats were central to the planning process. Studies show that artificial lighting can disrupt bats’ movement, feeding, and navigation, with short-wavelength light, such as blue, green, or white, having the strongest impact. Research from the Netherlands suggests red light, which has longer wavelengths, is likely to be less disruptive to bat behaviour.

In addition, it is expected to be more convenient for bats to hunt insects. Flagging safety, officials highlighted that completely turning off the lights was not an option. Instead of turning the light off, the red light was the best choice.

Although sections of the road have shifted to red lighting, ensuring safety for motorists and cyclists remains central to the design. Warm white lights continue to be used at intersections and pedestrian crossings, mounted on taller poles to enhance visibility in high-risk areas. The lighting setup changes along the route, tailored to how different stretches are used by people and wildlife, avoiding a one-size-fits-all solution.

Jonas Jørgensen, a road engineer with Gladsaxe Municipality, stated that the aim was to minimise disruption while maintaining accessibility. He explained that while complete darkness would be best for bats, it is impractical on a public roadway. The approach, he added, strikes a balance between environmental protection and everyday needs, requiring careful planning rather than a simple lighting change.