Red lights at night: what Grand Teton visitors preferred

A parking lot at Grand Teton lit three ways: an old streetlight (front left), a red LED (middle) and a cool white LED (back). From Fristrup and others, Scientific Reports (2024), CC BY 4.0.

Visitors to Grand Teton National Park felt safer and more comfortable under red outdoor lights than under white ones — and thought red was better for wildlife. A 2024 study suggests parks can protect dark skies and night-time ecosystems without making people feel less safe.

The problem with light at night

Anyone who sleeps with blackout blinds or an eye mask knows how light at night gets in the way. Towns and cities are full of it — traffic lights, streetlights, security lamps — much of it useful, some of it more than anyone needs. Outdoor lighting brightens the night sky far beyond where people live, and in national parks it spills into the natural areas next door, where it can disrupt ecosystems and wildlife.

LED lighting is efficient and controllable, but much of it is rich in blue light, which carries far and affects animals strongly.

The experiment

Researchers installed two kinds of experimental LED lighting in Grand Teton — plain white, and a blend of red and white — and asked visitors what they thought of each.

The results suggest that the usual worry — that dimmer or warmer light will make visitors feel unsafe — need not stand in the way of switching to lighting that is kinder to the night.

Sources

Written from "Visitors to Grand Teton National Park Prefer Red LED Lights at Night", by the editors of Park Science magazine, Volume 39, Number 1 (Winter 2024–25), National Park Service. The study: K. M. Fristrup and others, "National Park Visitors Perceive Benefits for Themselves and Wildlife under Blended Red-White Outdoor Lighting", Scientific Reports 14: 21791 (2024), doi:10.1038/s41598-024-71868-4.