Switching to red street lighting could cut light pollution and help wildlife
Streetlights are becoming brighter and more “white.” Many cities have replaced older orange sodium lamps with blue-rich LED lighting. The change cuts power use, but it also reshapes the night for insects, birds, and other wildlife. Scientists warn that artificial light at night is spreading quickly. A major review cited in a recent field project estimates that night-sky brightness has been increasing by roughly 9.6% each year.
A different approach is now drawing attention: shift away from cool white light and use red or red-leaning streetlighting instead. The aim is practical to keep roads visible while lowering the damage to wildlife.
What studies are showing
In 2024, researchers ran a test at Colter Bay Village in Grand Teton National Park using a “blended red-white” streetlight system. The lamps could switch between standard white light and a red-tilted blend. The red option used narrowband LEDs peaking near 623 nm, paired with two warm-white LEDs. Importantly, the two settings were designed to be similar in luminance.
Visitors were asked to share how the lighting felt. The results challenged assumptions: people scored the red-leaning setup higher for comfort and perceived safety, even though the scene looked dimmer to them.
A National Park Service summary also highlights a key point: overly bright lighting can actually reduce night vision. Moving from bright pools of light into darker zones forces the eyes to constantly re-adjust. Warmer, more even lighting can protect night adaptation and make those transitions easier.
A follow-up study in 2025 at the same site looked at insects and other arthropods. Researchers replaced 32 streetlights and compared standard white light (3000 K) with blended red lighting. The traps caught fewer arthropods under the blended red lights than under the white lights.
That matters because insects sit near the base of many food webs. When insect activity drops, the effects can spread to birds, bats, and other species that rely on them.
Why red light may be less disruptive
Many insects are especially attracted to shorter wavelengths, such as blue and ultraviolet. Bats can also shift their hunting patterns around bright, broad-spectrum lamps, partly because insects cluster around those lights. Red-leaning lighting reduces the short-wavelength portion of the spectrum, which can mean less disruption to wildlife and less glow in the night sky.
This idea is already being used in practice. In the Netherlands, the town of Zuidhoek-Nieuwkoop installed bat-friendly streetlights that emit red lights that bats perceive more like darkness, while still providing enough visibility for people on roads and walkways.
What cities are testing now
In early 2026, Gladsaxe near Copenhagen began installing red-spectrum LEDs along a road segment and cycle route close to bat habitat. The project is positioned as a balance: keep guidance lighting for cyclists and pedestrians, but reduce interference with bats. The design is also being adjusted for safety at crossings; extra poles were added to create clearer cues and improve awareness.
Denmark is not the only place experimenting. Cities in the Czech Republic and Sweden are testing “biodynamic” systems that shift colour across the night. As 2026 progresses, the direction is clear: light only what we must, and leave more darkness for nature.
Choosing red light is not just a technical swap. It reflects a wider mindset of designing cities that protect both human safety and the living world after sunset.
#RedStreetLights #LightPollution #WildlifeConservation #Bat-friendlyLighting #LEDLightWavelengths #OneHealthEnvironmentalImpact #BiodynamicLighting #EcosystemDisruption #NocturnalAnimalBehavior #PublicSafetyLighting #DarkSkyInitiatives
Switching to red street lighting could cut light pollution and help wildlife
Streetlights are becoming brighter and more “white.” Many cities have replaced older orange sodium lamps with blue-rich LED lighting. The change cuts power use, but it also reshapes the night for insects, birds, and other wildlife. Scientists warn that artificial light at night is spreading quickly. A major review cited in a recent field project estimates that night-sky brightness has been increasing by roughly 9.6% each year.
A different approach is now drawing attention: shift away from cool white light and use red or red-leaning streetlighting instead. The aim is practical to keep roads visible while lowering the damage to wildlife.
What studies are showing
In 2024, researchers ran a test at Colter Bay Village in Grand Teton National Park using a “blended red-white” streetlight system. The lamps could switch between standard white light and a red-tilted blend. The red option used narrowband LEDs peaking near 623 nm, paired with two warm-white LEDs. Importantly, the two settings were designed to be similar in luminance.
Visitors were asked to share how the lighting felt. The results challenged assumptions: people scored the red-leaning setup higher for comfort and perceived safety, even though the scene looked dimmer to them.
A National Park Service summary also highlights a key point: overly bright lighting can actually reduce night vision. Moving from bright pools of light into darker zones forces the eyes to constantly re-adjust. Warmer, more even lighting can protect night adaptation and make those transitions easier.
A follow-up study in 2025 at the same site looked at insects and other arthropods. Researchers replaced 32 streetlights and compared standard white light (3000 K) with blended red lighting. The traps caught fewer arthropods under the blended red lights than under the white lights.
That matters because insects sit near the base of many food webs. When insect activity drops, the effects can spread to birds, bats, and other species that rely on them.
Why red light may be less disruptive
Many insects are especially attracted to shorter wavelengths, such as blue and ultraviolet. Bats can also shift their hunting patterns around bright, broad-spectrum lamps, partly because insects cluster around those lights. Red-leaning lighting reduces the short-wavelength portion of the spectrum, which can mean less disruption to wildlife and less glow in the night sky.
This idea is already being used in practice. In the Netherlands, the town of Zuidhoek-Nieuwkoop installed bat-friendly streetlights that emit red lights that bats perceive more like darkness, while still providing enough visibility for people on roads and walkways.
What cities are testing now
In early 2026, Gladsaxe near Copenhagen began installing red-spectrum LEDs along a road segment and cycle route close to bat habitat. The project is positioned as a balance: keep guidance lighting for cyclists and pedestrians, but reduce interference with bats. The design is also being adjusted for safety at crossings; extra poles were added to create clearer cues and improve awareness.
Denmark is not the only place experimenting. Cities in the Czech Republic and Sweden are testing “biodynamic” systems that shift colour across the night. As 2026 progresses, the direction is clear: light only what we must, and leave more darkness for nature.
Choosing red light is not just a technical swap. It reflects a wider mindset of designing cities that protect both human safety and the living world after sunset.
#RedStreetLights #LightPollution #WildlifeConservation #Bat-friendlyLighting #LEDLightWavelengths #OneHealthEnvironmentalImpact #BiodynamicLighting #EcosystemDisruption #NocturnalAnimalBehavior #PublicSafetyLighting #DarkSkyInitiatives
