The color of street lights

In places like Denmark, municipalities are installing warmer, reddish lighting that reduces light pollution while still maintaining visibility for pedestrians and drivers. This shift is not just aesthetic. Scientific research shows that traditional white and blue-rich lighting can disrupt wildlife behavior — particularly for bats, insects, and migrating birds — while red light has far less impact, allowing these species to function almost as if in natural darkness.

The PBS report highlights another important benefit: these systems can be more energy-efficient and require less maintenance, offering cities a cost-effective sustainability solution alongside ecological gains.

San Mateo sits within a region rich in biodiversity, with nearby wetlands, bay habitats, and wildlife corridors that are increasingly stressed by urban expansion. Artificial light at night is a growing but often overlooked environmental issue, one that disrupts natural circadian rhythms and contributes to broader ecological imbalance.

A pilot program — perhaps along Bayfront trails, park edges, or sensitive habitat zones — could allow San Mateo to evaluate red-spectrum lighting locally. This would position the city as a forward-thinking leader in balancing public safety, energy efficiency, and environmental stewardship.

We often think of sustainability in terms of cars, buildings, or energy sources. But sometimes, meaningful change comes from something as simple as the color of the light above our streets.

Elaine Salinger

San Mateo