A Revolutionary Animal Overpass Is Rising Over L.A.’s Busiest Freeway

Each year, between one and two million vehicle collisions with large animals occur in the U.S., resulting in hundreds of human fatalities and even more animal deaths. Wildlife crossings—human-made structures that help animals safely cross roads—have the potential to significantly reduce these deadly collisions. An ambitious project in California is developing the world’s largest wildlife crossing, and they’ve just achieved a crucial step.

Crews working on the Wallis Annenberg Wildlife Crossing have begun laying 6,000 cubic yards of soil on the structure, which will facilitate the future growth of native vegetation and encourage wildlife use. Once it’s complete, the crossing will span ten lanes of U.S. Highway 101 in Agoura Hills, Los Angeles County. California Governor Gavin Newsom announced the milestone in a statement published Wednesday.

“California is a state of dreamers and doers—and with the Wallis Annenberg Wildlife Crossing, we’ve turned our dreaming into doing. As soil gets placed over the bridge, we’re one step closer to reconnecting wildlife with habitat that’s been divided for generations,” Newsom said. “We’re not only making habitats whole again, we’re making our roads safer.”

In 1990, the Santa Monica Mountains Conservancy commissioned a study identifying the area near Agoura Hills’ U.S. 101 and Liberty Canyon Road as a critical location for a wildlife crossing to help prevent the extinction of local mountain lions, according to the conservancy. A crossing was deemed necessary to connect the Santa Monica Mountains to the Simi Hills on the other side of the 101 Freeway, or else wildlife in the mountains would remain trapped.

“Humans created this problem,” said Jeremy Wolf, mayor pro tempore of Agoura Hills, as reported by the Los Angeles Times. Wolf witnessed the soil’s arrival last week. “We’ve created islands of habitat fragmentation with our roadways and housing encroaching deeper and deeper into the wild urban interface, and now we’re fixing this problem by using human ingenuity for good purposes.”

In addition to mountain lions, the Wallis Annenberg Wildlife Crossing will facilitate safe passage for species such as deer, bats, bobcats, monarch butterflies, and desert cottontails between habitats. The soil will support the planting of approximately 5,000 native plants, including coastal sage scrub species, on the crossing, with planting expected to begin as early as May.

“Wildlife crossings are unique because they allow people and nature to thrive together,” said California Department of Transportation (Caltrans) Director Tony Tavares. Caltrans is an important partner on the public-private habitat project. “By building the Wallis Annenberg Wildlife Crossing, Caltrans is supporting transportation infrastructure that will not only reconnect and restore habitats but also reduce vehicle collisions with wildlife and enhance highway safety.”

The monumental project stands as a reminder that infrastructure can and should coexist with the natural world.