California Wildlife Bridges: Protecting Ecosystems and Preventing Accidents

California is nearing the completion of the Wallis Annenberg Wildlife Crossing, a project designated as the world’s largest wildlife crossing. Situated over U.S. Highway 101, the structure is the first of its kind in California and is designed to reduce wildlife-vehicle collisions while supporting the long-term viability of local species by facilitating natural movement.

According to a report from the state government published on February 2, 2026, the Annenberg project is described as an ambitious effort to bridge the gap between conservation and urban development.

Statewide Connectivity Infrastructure

The Annenberg crossing is part of a broader statewide effort to improve animal migration and road safety. California currently maintains over 1,500 wildlife crossing structures, which include a variety of underpasses and overpasses distributed across the state.

The California Department of Transportation, known as Caltrans, is currently managing 31 active funded projects aimed at improving wildlife connectivity. This current activity follows a 2024 report that identified a total of 144 crossing efforts needed across the state to adequately protect biodiversity and animal populations.

The Role of Wildlife Corridors

Wildlife corridors are designed to connect animal habitats that have been separated by human infrastructure. As roads and fences divide large habitats, wildlife populations can become boxed into smaller areas, which limits their movement and increases the risk of fatalities.

These corridors can take several forms depending on the environment and the species they are intended to serve:

• Vegetated highway overpasses, such as grass-covered bridges that allow animals to cross busy freeways safely.
• Riparian buffer strips located along rivers.
• Underwater swimways.

By providing these safe passages, the state aims to protect both individual animals and broader ecosystems, reducing the frequency of vehicle accidents and supporting overall biodiversity.

Regional Conservation Projects

Beyond the Annenberg project, Caltrans is implementing targeted infrastructure in other high-risk regions. In Siskiyou County, the department is constructing Northern California’s first wildlife overcrossing bridge on U.S. Highway 97.

This specific project area was identified as having a high rate of wildlife-vehicle collisions, particularly involving elk in Caltrans District 2. The California Department of Fish and Wildlife utilized its Areas of Conservation Emphasis mapping tool to designate the project site as irreplaceable and essential.

Similarly, wildlife crossing initiatives in Humboldt County and surrounding areas are focused on the U.S. Highway 101 corridor. These efforts specifically target the reduction of high-frequency collisions involving black bears and Roosevelt elk.

These combined efforts reflect a strategic shift in transportation infrastructure and urban planning, prioritizing sustainable development and species preservation to ensure that roads do not remain permanent barriers to wildlife migration.