How P-22's Hollywood Story Became the World's Largest Wildlife Crossing

In 2012, a mountain lion known as P-22 crossed two of Los Angeles's busiest freeways and became an unlikely local celebrity. The cougar's story drew attention to a brutal reality: highways such as the 101 and 405 had separated his population and pushed isolated groups toward local extinction. Beth Pratt, then newly appointed head of the National Wildlife Federation's California branch, started asking how a safe wildlife corridor over the 101 could be built.

Fourteen years later, the answer is the Wallis Annenberg Wildlife Crossing, scheduled to open in December. The vegetated overpass will span the 10-lane Ventura Freeway, measure 210 feet, and cost more than $100 million. It is designed for mountain lions, coyotes, deer, and black bears, and it will be the largest animal crossing in the world.

The project is no longer an isolated California oddity. Since 2012, more than 1,000 wildlife corridors have been built across the United States, ranging from an elk overpass on Colorado's Interstate 25 to small tunnels for migrating toads in New Jersey. In 2021, the federal government created the $350 million Wildlife Crossings Pilot Program under the infrastructure law, a sign that the idea has moved from philanthropy-funded experiments to formal transportation policy.

Wallis Annenberg and the Shift in American Road-Building Norms

How P-22 Turned a Local Overpass Into Federal Policy

The Wallis Annenberg crossing began as a difficult, celebrity-powered campaign rather than a routine road project. California's transportation agency was initially baffled by the proposal, and the combination of complex engineering, philanthropic funding, and rising construction costs made it more expensive than it needed to be. Yet that highly visible struggle became a proof of concept: the project helped inspire more than 1,000 corridors nationally and a dedicated federal pilot program that is now up for renewal.

Why Caltrans and Other Transportation Agencies Changed Their View

Road ecology researcher Marcel Huijser argues that the real change is cultural. In the Netherlands, wildlife crossings have been standard for decades, but American planners historically treated ecological impacts as an afterthought. The Wallis Annenberg project has made that position harder to defend. Caltrans now has a division explicitly dedicated to wildlife crossings, and Pratt points out that many future fixes can be far simpler, such as small culverts, fence adjustments, or pollinator-friendly openings that fit into existing maintenance work.

The Renewal Fight and the 'Butterfly Bridge' Backlash

The project's policy legacy now depends on whether crossings become normal budget items rather than exceptions carried by famous advocates. The federal Wildlife Crossings Pilot Program appears likely to become permanent around the time the bridge opens, which would give state agencies a recurring funding route. At the same time, the backlash is real: Pratt received death threats after right-wing media framed the bridge as a wasteful 'butterfly bridge.' That reaction shows bipartisan support for safety infrastructure exists but is fragile when projects are presented as environmental symbolism rather than collision prevention.

The Policy Window for States and Agencies as the Crossing Opens

For state transportation agencies and local officials, the December opening creates a concrete policy window rather than simply a ceremonial milestone:

  • Prepare for the federal funding stream. The $350 million Wildlife Crossings Pilot Program is up for renewal and expected to become permanent, so state agencies that have not developed crossing projects should prepare applications rather than relying on philanthropic or one-off state money.
  • Copy Caltrans's lower-cost model, not just the $100 million overpass. The article notes that small culverts, fencing changes, and pollinator stops can be added within existing road-maintenance work; Caltrans now has a dedicated wildlife crossings division to support this shift.
  • Frame projects as road safety. For drivers near the Ventura Freeway segment, the Wallis Annenberg crossing is an animal passage, not a public recreation space. The immediate public benefit is reduced wildlife-vehicle collision risk on a dangerous 10-lane corridor when it opens in December.