Three years since the construction of the Wallis Annenberg Wildlife Crossing began in Southern California, the first layers of soil were placed over the bridge in April 2025. The total soil placement for the project will require approximately 6,000 cubic yards and will take several weeks to complete.
Construction of the crossing, which began in April 2022, will result in the largest wildlife crossing in the world and the first of its scale in an urban area. The wildlife crossing will span ten lanes of pavement over the 101 freeway, along with the Agoura Road – one of the largest and busiest highways in North America. The main crossing structure will be 210-foot-long across the freeway, and scale 170 feet in width along the freeway.
The primary goal of the project is to save a population of mountain lions from extinction by providing a connection between the small and isolated population in the Santa Monica Mountains to a larger and more genetically diverse population to the north. The ecological corridor will also support a variety of other local wildlife including deer, bats, bobcats, desert cottontails, monarch butterflies and more. Weather permitting, planting of approximately 5,000 native plants will begin in May 2025.
The Wallis Annenberg Wildlife Crossing project is managed by Caltrans, which also oversees all aspects of construction. The entire wildlife crossing is estimated to be completed in 2026. Although originally slated for completion in 2025, progress on the project for two springs in a row was substantially impacted by record precipitation and flooding events.
Track the construction progress in real time:
https://101wildlifecrossing.org
https://app.oxblue.com/?openlink=NWF/WallisAnnenbergWildlifeCrossing
“Wildlife crossings are unique because they allow people and nature to thrive together,” said Tony Tavares, Director, Caltrans. “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 Wallis Annenberg Wildlife Crossing is a public-private partnership that has leveraged the expertise of organizations from across the world. The core project partner team includes Caltrans, the National Park Service, the Santa Monica Mountains Conservancy / Mountains Recreation & Conservation Authority, and the National Wildlife Federation. The project partners also added a world-renowned design team led by a landscape architectural practice, Rock Design Associates, that collaborates with Caltrans and coordinates with a broad team of wildlife crossing experts in the planning, design and construction of the wildlife crossing.
First-ever program to improve safety on America’s roadways by preventing wildlife-vehicle collisions
In April 2023, the Biden administration unveiled the Wildlife Crossings Pilot Program, the first-of-its-kind pilot program to make roads safer, prevent wildlife-vehicle collisions, and improve habitat connectivity on U.S. roads. The program, established under the Bipartisan Infrastructure Act of 2021 and administered by the Federal Highway Administration, will provide $350 million over five years to build underpasses, overpasses, and other wildlife structures.
The grant funding will promote activities that reduce wildlife vehicle collisions, including warning signs for drivers and construction of wildlife crossings both over and under roadways where habitats exist on either side of a busy road. Grants are available for all project activities, including but not limited to research, planning, design, and construction. The Federal Highway Administration seeks to award non-construction and construction projects under the Wildlife Crossings Program, including research on safety innovations, mapping and tracking tools, and the design and construction of overpasses and underpasses.