Drive along one road in Gladsaxe, a suburb of Copenhagen, at night and the scene looks almost unreal: the streetlights glow red. It’s not a festival or a mistake. The town made the choice on purpose, for neighbors most residents never see.
In short
- Gladsaxe, in Denmark, installed red street lighting on Frederiksborgvej, near a natural area.
- The goal is to limit the effect of light on bats and other nocturnal, light-shy species.
- Studies on bat-friendly lighting indicate red light disturbs wildlife less.
- People can still find their way and keep their night vision.
A road next to a natural area
The project sits on Frederiksborgvej, near Skovbrynet, according to AFRY’s newsroom. Gladsaxe Municipality put it in place as part of its work on the UN Sustainable Development Goals, with lighting designed by Light Bureau.
The reason is the wildlife living along the road. The municipality switched to red light to limit behavioural effects on bats and other nocturnal species that avoid light.
Why red?
White light at night can disrupt animals that live in the dark. Studies on bat-friendly lighting indicate that red light disturbs wildlife less, while still letting people find their way and preserving their night vision, AFRY reports.
For the designers, the color also carries a message. “The red light should make passers-by aware that this is a special natural area that we want to protect,” said Philip Jelvard, lighting designer at Light Bureau. He added that the red light has a symbolic value as well as a functional one, and said the team hopes people will welcome it. Bats are not the only ones concerned: the municipality also mentions other nocturnal species that shy away from light.
More than an energy story
Changing streetlights is often about cutting costs. Here, the motivation is different, which is why the project caught attention far beyond Denmark, including in the U.S. press: “How Denmark’s Red Streetlights Do A Lot More Than Save Energy,” Jalopnik titled. It’s a reminder that outdoor light affects more than people.
The same principle can apply in our own backyards. If you enjoy the wildlife that comes out after dark, the brightness and color of your outdoor lights are worth a thought, especially in a garden next to trees or open land.
Lighting choices matter at home, too. The lights we add outside for the season can have consequences we don’t expect, as electricians point out about string lights wrapped around the porch railing. And backyard wildlife has its own winter challenges, like the chickadees that struggle with the cold.
The limit
AFRY’s article describes the reasons behind the project, not measured results: we didn’t find data showing how bat activity changed on this road. Red lighting is used here on one specific stretch near a natural area, not across the whole town. Street lighting rules also differ from one country to another, so this is an idea to understand rather than something homeowners can copy on public roads. And bat-friendly lighting is an evolving field, with recommendations that can vary by species and location.
That’s the story.
