Agoura Hills wildlife crossing bridge over 101 Freeway to open this winter

The Wallis Annenberg Wildlife Crossing — a nearly 1-acre structure expected to reconnect areas used by SoCal’s wild animals — will open to wildlife on Dec. 2 after years of planning and construction.

Construction began on Earth Day in 2022. Once completed, the bridge will allow all forms of wildlife to safely cross the busy 101 Freeway in Agoura Hills, from mountain lions and bobcats to birds and butterflies.

Beth Pratt, regional executive director at the California Regional Center with the National Wildlife Federation, said the crossing is unlike any other wildlife crossing in the country.

“This project is four projects in one, and it is of a complexity, coordination and magnitude that is off the charts,” Pratt said. “The Santa Monica Mountains are one of 36 biodiversity hot spots in the world, and we designed this for an array of wildlife so that all wildlife in this region would have a future.”

The project’s cost is around $90 million to $100 million, and is considered one of the most expensive wildlife crossings in the world.

Officials with the Wallis Annenberg Wildlife Crossing announced Wednesday that SoCal animals will be able to traverse the crossing on Dec. 2, 2026.

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Destiny Torres

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LAist

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Why it matters 

Jeff Sikich, a wildlife biologist with the National Park Service, told LAist that the mountain lion population is small and isolated in the Santa Monica Mountains, and the 101 Freeway is a major barrier for movement.

“We don't have many lines from north of the freeway crossing south, so that can lead to very low genetic diversity. We have documented inbreeding fathers breeding with daughters and granddaughters,” Sikich said. “It's not a numbers problem in the Santa Monica Mountains here … It's a genetic diversity issue.”

Vehicle strikes are the leading cause of death for this mountain lion population, Sikich added. The bridge will allow animals born in the Santa Monica Mountains, especially those with diverse genetics, a safe way to leave.

Officials with the Wallis Annenberg Wildlife Crossing announced Wednesday that SoCal animals will be able to traverse the crossing on Dec. 2, 2026.

(

Destiny Torres

/

LAist

)

What’s next? 

Construction of the first structure is complete, and crews are now building the second half over Agoura Road. That second structure is expected to go up over the summer.

Robert Rock of Rock Design Associates said crews are using methods to reduce effects to drivers who rely on the 101 Freeway.

“We had precast box girders that were built at a facility in Perris, California, that were all essentially giant concrete Legos that came and got placed,” Rock said. “That reduction in impact to the traveling public was a key deciding factor that motivated how we changed the design.”

Next, crews will move three million cubic feet of soil to regrade the land surrounding the site.

A lot of the work on the second structure has been happening 60 to 100 feet underground, Rock added.

“As we get to the end of the summer, I think people will start to see how much transformation actually is occurring on the site because we'll have met that moment in the schedule where all that work is coming back up to the point where you'll be able to see it from the freeway again,” he said.