Construction underway for world's largest wildlife crossing, 30 years in the making

A rendering of the Wallis Annenberg Wildlife Crossing in California, viewed from the highway

In 2022, seven mountain lions were killed in Los Angeles area traffic, including the famous P-22, whose death became a catalyst for animal lovers to act.

Wildlife activists, government agencies, and private donors came together to finally create a solution to urban wildlife deaths: The Wallis Annenberg Wildlife Crossing.

The crossing is slated to be the world’s largest wildlife crossing, spanning the busy 101 freeway in Agoura Hills. 

A rendering of the Wallis Annenberg Wildlife Crossing
Photo courtesy of Rock Design Associates and National Wildlife Fedeartion

Crews broke ground on the crossing on Earth Day two years ago, and last month, California Governor Gavin Newsom announced that the crossing is on track to open by early 2026. Construction crews are more than halfway through installing the enormous bridge’s beams — of which there will be 82.

Additionally, the final horizontal girders of the crossing were added into place last month, completing an important phase in construction, and making the crossing look even more like a bridge.

A side by side rendering of the before - construction - and completion stages of the Wallis Annenberg Wildlife Crossing
Photo courtesy of the office of Governor Gavin Newsom

“Our work to build more, faster is already paying dividends across our state. This wildlife crossing is just one example of how California is building infrastructure that connects rather than divides,” Gov. Newsom said in a statement in May.

“With projects like this, we’re reconnecting and restoring habitats so future generations can continue to enjoy California’s unmatched natural beauty.”

A group of stakeholders, including Gavin Newsom, break ground on the Wallist Annenberg Wildlife Crossing in California
Governor Gavin Newsom (second from the left) breaks ground on the crossing, alongside stakeholders and advocates. Photo courtesy of Amber Canterbury/National Wildlife Federation

While construction seems to be fast-moving, it took decades of advocacy by wildlife groups to finally bring the bridge to fruition. It has a $90+ million price tag, covered by $34 million in private funding, and $58.1 million from the state. 

A birds-eye-view of the world's largest wildlife crossing during construction
Crews finished adding horizontal girders to the bridge in May. Photo courtesy of Caltrans

Long-time advocates spent years convincing decision-makers that this was a small price to pay to protect wildlife.

“Let’s use this opportunity to congratulate the many advocates and environmental leaders, past and present, who spent years working with local, state, and federal officials to protect and preserve the Santa Monica Mountains and Simi Hills for future generations of people and wildlife,” said retired California State Senator Fran Pavley, following  years of advocacy for the area’s wildlife

“Reconnecting these large islands of habitat on both sides of the busy 101 freeway is an almost unbelievable story, especially in the most populated county in the U.S.”

Like other wildlife crossings, the Wallis Annenberg will provide a safe passage for wild animals to move across the freeway without the threat of being hit by oncoming traffic. 

A rendering of mountain lions using the world's largest wildlife crossing
Photo courtesy of Rock Design Associations and the National Wildlife Federation

The National Parks Service has spent over 20 years studying the impact of freeways and traffic on the area’s mountain lions, concluding that without safe passage options, mountain lions could vanish from the area within our lifetimes.

Fortunately, studies show that other wildlife crossing structures throughout North America have led to a 86-97% decrease in wildlife-vehicle collisions

Wildlife crossings don’t just reduce car crashes. By allowing for safe passage, animals — like mountain lions — can find food, shelter, and mates, necessities that have become harder to obtain amid climate change and human development.

Mountain lion P-22 roams California at night
Beloved mountain lion P-22. Photo courtesy of Miguel Ordenana/National Wildlife Federation

As the Wallis Annenberg nears completion of Stage 1 of construction, it’s becoming even more apparent just how impactful this structure has the potential to be. The bridge is planned to be 210 feet long and 174 feet wide, long enough to accommodate about five to six lanes in each direction if the bridge were designed to carry traffic.

“This visionary structure will preserve biodiversity across the region by connecting an integral wildlife corridor, and most immediately critical, help save a threatened local population of mountain lions from extinction,” the crossing’s website explained.

“When complete, the crossing will be the largest in the world, the first of its kind in California, and it will serve as a global model for urban wildlife conservation.”

A rendering of the Wallis Annenberg Wildlife Crossing in California, viewed from the highway
Photo courtesy of Rock Design Associates and the National Wildlife Federation

Drivers on the 101 will likely experience the crossing as if they were driving through a tunnel, but for local species, it will appear like a natural hillside covered with native vegetation. The crossing is planned to be built like a habitat itself, rather than a mere path connecting the two natural areas, according to SFGate.

With 30 years of conservation work fueling the design of the crossing, stakeholders are hopeful that it will make an impact on the future of urban wildlife solutions.

In fact, the Save LA Cougars campaign recently launched a new fundraising effort for additional crossings in Southern California. 

Beth Pratt speaks at the ground-breaking of the Wallis Annenberg Wildlife Crossing
Beth Pratt. Photo courtesy of the National Wildlife Federation

And for those who have spent years working toward this major victory, it is simply one (giant) pathway to a more wildlife-friendly future.

“You’re going to see this ecological transformation… over one of the busiest freeways in the world,” said Beth Pratt, a regional executive director for the National Wildlife Federation in California, who spent over 10 years advocating for the crossing.

“That, to me, is just such a hopeful statement for what’s possible. We can redeem a freeway.”

Header image courtesy of Rock Design Associates and the National Wildlife Federation

Article Details

June 5, 2024 12:55 PM
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