Travis Longcore for California Builder & Engineer—Caltrans to Restore Habitat Connectivity Across One of the Busiest Freeways in the World

Travis Longcore, adjunct professor at UCLA Institute of the Environment and Sustainability, discussed light pollution mitigation at the Wallis Annenberg Wildlife Crossing for California Builder & Engineer, sharing how thoughtful infrastructure design can help reestablish habitat connectivity for wildlife in urban areas.

Longcore and his team of researchers observed an American barn owl fly across 101 Freeway through a “dark spot” over the under-construction crossing — early evidence that efforts to create a safe, dim environment for wildlife are already showing promise.

“We saw the owl swoop around us while walking down a ridgeline,” Longcore said. “One researcher observed the owl cross the 101 by flying directly through a dark spot over the newly completed bridge span. It was a special moment to realize that we were there when the first wildlife use — even if in the air — was observed.”

Longcore’s work is part of a larger collaboration between Caltrans, the National Wildlife Federation and design experts to ensure the crossing allows wildlife to safely traverse one of the busiest freeways in the world by mimicking the surrounding ecosystem. His research has helped inform lighting strategies such as using amber-colored bulbs and reducing surface reflectivity to minimize sky glow — crucial steps for creating a nighttime environment conducive to animal movement.