World's Largest Animal Bridge Takes Shape in California

Gateway to Safety

California's ambitious project to address animal-vehicle collisions, which claim over a million wildlife lives and result in 200 human fatalities and 26,000 injuries annually, is underway. The Los Angeles County segment of Highway 101 is set to be crossed by the world's largest animal overpass, as reported by the Smithsonian on April 24.

Aerial Lifeline

Upon completion in 2025, this "nature bridge" will provide a safe passage for mountain lions, bobcats, deer, lizards, coyotes, snakes, and insects between the Santa Monica Mountains and the Simi Hills across the Santa Susana Mountains. Named the Wallis Annenberg Wildlife Crossing, the project is a $92 million collaboration between Caltrans, the National Park Service, and the National Wildlife Federation.

Milestone Reached

Construction began on Earth Day two years ago, and last week, a major milestone was reached when the first span of the bridge was lifted into place over the highway. Over the coming months, crews will install additional concrete girders, each weighing between 126 and 140 tons. The 210-foot bridge will span eight lanes of traffic. Ultimately, the structure will be adorned with over one million native plants to attract wildlife. The project also includes landscaping on 12 acres adjacent to the overpass, creating a more natural hillside appearance rather than a bridge-like feel.

Lion Lifeline

While the bridge will benefit a wide range of animals, experts are particularly hopeful for its impact on mountain lions. These animals naturally roam territories spanning up to 100 square miles. However, due to the extensive network of freeways in Los Angeles, their movement is severely restricted. As a result, mountain lions in the area are experiencing inbreeding, leading to increased health issues. Without improved genetic diversity, these big cats could disappear from the region.

P-22's Legacy

In recent years, the story of a famed mountain lion named P-22 has garnered significant attention. Born in 2010, P-22 was forced to navigate at least two busy freeways to reach his den in Griffith Park, Los Angeles. He spent over a decade roaming a small, isolated territory, with no apparent hope of finding a mate. In December 2022, P-22 was euthanized after attacking two domestic dogs. Necropsy results revealed that he had sustained multiple vehicle-related injuries, a fractured skull, kidney disease, arthritis, and other chronic conditions. His story has inspired numerous individuals and organizations to contribute to the Wallis Annenberg Wildlife Crossing project.