State wildlife officials and the Wildlife Crossing Fund have reached a milestone in planning a series of highway overpasses and underpasses on U.S. Route 395 near Mammoth Lakes, California. The project aims to mitigate vehicle-wildlife collisions for the Casa Diablo and Round Valley mule deer herds, which frequently cross the high-traffic corridor between mountain summer ranges and desert winter habitats.
The Ecological Stakes of the U.S. 395 Corridor
U.S. Route 395 serves as a vital artery for human transit, but it also bisects the essential migration paths of the Eastern Sierra’s wildlife. According to Beth Pratt, president and CEO of the Wildlife Crossing Fund, a 10.5-mile stretch near Mammoth Lakes is a documented “roadkill hotspot.” The impact extends beyond mule deer; the area is home to mountain lions, black bears, coyotes, and threatened species like the sage grouse. The California Department of Fish and Wildlife identified this segment as a priority for addressing movement barriers in its 2022 list, citing the impact on mule deer, mountain lions, black bears and sage grouses.
Did you know?
In 2023, an estimated 48,442 mule deer were killed in vehicle collisions on California roads, accounting for more than 10% of the state’s total population, according to a 2024 report by the UC Davis Road Ecology Center.
Engineering Solutions for Wildlife Connectivity
The proposed infrastructure plan focuses on two specific sites: an overpass at Morrison Hill and an underpass at Convict Creek. These structures, complemented by strategic fencing and “jump outs” to guide animals safely away from traffic, are designed to restore habitat connectivity. Caltrans completed the initial design phase this spring with the support of a $3.17 million grant from the Wildlife Conservation Board.
The project faces a substantial financial hurdle, with total construction costs estimated at $84 million. While the Wildlife Crossing Fund has secured $1 million for the next phase of design and engineering, the organization continues to seek funding to close the gap. Pratt notes that the successful development of the Wallis Annenberg Wildlife Crossing in Los Angeles serves as a precedent, demonstrating how high-visibility infrastructure can shift public perception and secure momentum for rural crossing projects.
Future Trends in Road Ecology
The shift toward wildlife-friendly infrastructure is gaining national traction. By prioritizing “wildlife connectivity,” state agencies and advocacy groups are moving toward a model that views roadkill not as an inevitable byproduct of travel, but as a “preventable natural disaster,” as described in the 2024 UC Davis Road Ecology Center report.
Pro Tip:
When driving through known migration corridors like the Eastern Sierra, maintain lower speeds.
Frequently Asked Questions
Why is U.S. 395 considered a dangerous area for wildlife?
The highway cuts directly through traditional migration routes used by mule deer and other wildlife to travel between high-elevation summer ranges and low-desert winter habitats. High vehicle speeds and heavy traffic volume make these crossings hazardous, leading to high mortality rates.
What exactly is a wildlife crossing?
Wildlife crossings include overpasses and underpasses specifically designed to allow animals to bypass roads safely. These are typically paired with exclusion fencing that guides wildlife toward the safe passage and away from the highway.
How long until the Mammoth Lakes crossings are completed?
According to Beth Pratt, the goal is to break ground on the project within two to three years, depending on the progress of design, engineering, and funding milestones.
What species besides deer use these crossings?
The crossings are designed to benefit a wide range of local fauna, including mountain lions, black bears, coyotes, bobcats, foxes, and the threatened sage grouse.
Have you spotted wildlife while driving through the Eastern Sierra? Share your thoughts on the importance of wildlife crossings in the comments below, or sign up for our newsletter to stay updated on the progress of the Mammoth Lakes project.
