For thousands of years, mule deer have followed seasonal migration routes across the Eastern Sierra Nevada, moving between high-elevation summer ranges and lower winter habitat.

Today, US Highway 395 intersects those historic pathways, creating the region’s most significant wildlife-vehicle collision hotspot and threatening one of California’s most important migration corridors.

The corridor affects far more than mule deer. Black bears, mountain lions, bobcats, Sierra Nevada red fox, and other wildlife also depend on safe movement through the region.

Rock Design Associates is a partner in the Eastern Sierra Wildlife Stewardship Team, a broad coalition of public agencies, conservation organizations, Tribal partners, local governments, and community stakeholders working to improve wildlife passage along this critical stretch of highway.

Proposed improvements include a wildlife overcrossing at Morrison Hill, an underpass at Convict Creek, wildlife-exclusion fencing, jump-outs, and Intelligent Transportation Systems designed to reduce collisions and improve habitat connectivity.

At Convict Creek, the project will also restore fish passage and strengthen riparian habitat by replacing an undersized culvert that has long disrupted ecological function.

US Highway 101 separates two of California’s most biologically important mountain ranges, limiting wildlife movement between the Santa Cruz Mountains and the Gabilan Range.

Near Rocks Road, this heavily traveled corridor has become a persistent barrier for mountain lions, deer, bobcats, and other species moving between protected habitats.

Rock Design Associates is supporting the development of a large wildlife overcrossing designed to restore movement across US 101 and connect thousands of acres of habitat with the permanently protected Rocks Ranch.

Working with the Land Trust of Santa Cruz County, Wildlife Conservation Network, and Caltrans District 5, RDA has provided technical review, site evaluations, and ecological guidance as the project advances into the PS&E phase.

Drawing on experience from wildlife crossing projects across the West, RDA is helping shape infrastructure that responds to both ecological and transportation needs.

The project represents an important opportunity to improve roadway safety, strengthen habitat connectivity, and support long-term movement between two major mountain systems.

Interstate 5 cuts across one of Southern California’s most important wildlife linkages, separating the Santa Susana and San Gabriel Mountains and restricting movement between hundreds of thousands of acres of habitat.

For mountain lions and dozens of other species, this heavily traveled corridor creates a significant barrier to movement across the landscape.

Restricted connectivity can limit genetic exchange, increase the risk of wildlife-vehicle collisions, and place additional pressure on wildlife populations already navigating a highly developed region.

Addressing that challenge requires more than identifying where animals cross. It means understanding habitat patterns, roadway conditions, engineering constraints, and the opportunities that exist along a complex transportation corridor.

Rock Design Associates is collaborating with the Mountains Recreation & Conservation Authority, The Nature Conservancy, Wildlife Conservation Network, South Coast Wildlands, and additional local stakeholders to develop an implementation plan for a 26-mile segment of I-5 between SR-138 and Castaic Creek.

The effort brings together landscape architecture, wildlife ecology, road ecology, engineering, and transportation planning to identify priority crossing locations, evaluate site feasibility, and advance the most promising opportunity toward Caltrans project development.

The Snyderville Basin supports seasonal wildlife movements that have shaped the landscape for generations.

Today, SR-224 serves as both the primary gateway to Park City and one of Utah’s most hazardous roadways for wildlife, with frequent collisions involving deer, elk, moose, and other species moving through the region.

As development and traffic increase, maintaining safe and functional wildlife movement across the corridor has become increasingly important.

Building on a completed Phase 1 Assessment, Rock Design Associates is working with Save People Save Wildlife to evaluate existing conditions, analyze wildlife movement patterns, and identify feasible crossing locations between Mile Markers 7 and 9.

With Park City preparing to host the 2034 Winter Olympics, future transportation improvements create an opportunity to address public safety, accessibility, and ecological connectivity together.

By integrating wildlife considerations into broader transportation planning, the project can help reduce conflict along the roadway while protecting the movement patterns that remain essential to the surrounding landscape.

The Gaviota Coast is one of California’s most ecologically rich landscapes, where rugged mountains meet the Pacific Ocean and wildlife depends on movement between inland habitats and the coast.

Within the Gaviota Creek watershed, this narrow coastal corridor supports a diverse network of terrestrial and aquatic species across one of the state’s last relatively undeveloped stretches of coastline.

US Highway 101 has become one of the watershed’s most significant barriers, limiting connectivity for species that rely on this passage.

Roadways, infrastructure, and other constraints can interrupt both fish and wildlife movement, making coordinated planning essential to restoring ecological function across the broader watershed.

Rock Design Associates is working with the Coastal Ranches Conservancy to evaluate projects throughout the Gaviota Creek watershed that improve both fish and wildlife movement.

The effort includes site assessments, coordination with Caltrans, state agencies, landowners, stakeholders, and technical guidance on opportunities to strengthen ecological connectivity, including proposed improvements near Gaviota State Park.

The Irvine-Laguna Wildlife Corridor represents one of Southern California’s most important opportunities to reconnect fragmented habitat.

Stretching from the Laguna Coast to Cleveland National Forest through the urban fabric of Orange County, the corridor links more than 170,000 acres of protected land. These landscapes support a diverse range of wildlife, from coastal bobcats to cactus wrens, while providing an essential connection between major habitat areas.

Interstate 5 near its intersection with the 405 Freeway represents the corridor’s greatest connectivity challenge.

Existing bridges, culverts, and tunnels were designed primarily for transportation and drainage rather than wildlife movement. As a result, one of Southern California’s busiest transportation corridors creates a significant barrier between otherwise connected natural landscapes.

Rock Design Associates is evaluating existing infrastructure, analyzing wildlife movement and collision data, and identifying opportunities to improve connectivity where it is needed most.

Working alongside Laguna Greenbelt, stakeholders, and project partners, RDA is developing targeted recommendations that explore how existing infrastructure can be adapted or enhanced to function more effectively for wildlife.

The Lake Tahoe Basin is renowned for its alpine landscapes, but it is also one of the Sierra Nevada’s most important wildlife movement corridors.

Black bears, bobcats, mule deer, and many other species depend on connected habitat to move through the region. As visitation and traffic continue to increase, highways including US 50, SR 89, and Pioneer Trail Road have become significant barriers across that landscape.

Rock Design Associates is working with the Wildlife Crossing Fund, California Tahoe Conservancy, Pathways for Wildlife, Caltrans, El Dorado County, the U.S. Forest Service, and the Washoe Tribe to advance environmental planning and compliance for up to four wildlife crossing structures throughout the South Tahoe Basin.

Guided by the California Tahoe Basin Wildlife Connectivity Study, the work focuses on locations where transportation infrastructure intersects with important wildlife movement routes.

The project seeks practical, science-based solutions that reconnect fragmented habitat while creating safer passage for wildlife across some of the region’s busiest transportation corridors.

By strengthening these connections, the work supports healthier wildlife populations and helps preserve the ecological systems that make the Lake Tahoe Basin distinctive.

For the Three Affiliated Tribes, also known as MHA Nation—the Mandan, Hidatsa, and Arikara Nation—the Missouri River system is more than a defining landscape. Its winding river, rugged Badlands, and crested clay buttes are inseparable from the Nation’s history, culture, and identity.

The acquisition of more than 2,000 acres of original treaty land marks a significant step toward establishing the Three Affiliated Tribes National Park and creates an opportunity to reconnect people with a landscape that has sustained the Nation since time immemorial.

Rock Design Associates is honored to support the MHA Nation Parks & Reserve Team in developing the master plan for the TAT National Park.

Through a collaborative planning process, the project brings together tourism, conservation, culture, heritage, ecological stewardship, and public experience. The goal is not simply to plan a new park, but to create a framework that reflects the significance of the land while honoring the stories, traditions, and relationships that continue to shape it.

The work extends beyond the boundaries of the park itself.

Supported by a USDOT BUILD grant, formerly known as RAISE, RDA is leading a multidisciplinary team to identify and prioritize transportation improvements along a five-mile segment of Highway 22. The effort considers how roadway improvements can enhance public safety while maintaining and strengthening wildlife movement across the surrounding landscape.

The Santa Monica Mountains are home to one of Southern California’s last remaining populations of mountain lions, along with countless other wildlife species that depend on connected habitat to survive. Over time, highways and development have divided this landscape into increasingly isolated fragments.

The 101 Freeway presents one of the region’s most significant barriers. Wildlife attempting to move between habitat areas faces the danger of vehicle collisions, while animals that remain isolated experience reduced access to food, territory, and potential mates. For mountain lions in particular, this fragmentation has contributed to dangerously limited genetic diversity.

The challenge was not simply to help animals cross a road. It was to reconnect a living ecological system that had been separated by infrastructure.

The Wallis Annenberg Wildlife Crossing was conceived as a piece of living infrastructure spanning the 101 Freeway in Agoura Hills. Rather than functioning as an ordinary bridge with landscaping added on top, the crossing is designed to continue the surrounding habitat across the freeway.

Its development brings together decades of scientific research, ecological planning, advocacy, engineering, and landscape design. Rock has directed the design since 2019, working closely with Caltrans District 7 on the final engineering documents and overseeing the project through construction.

RDA’s role has also included collaboration with scientists, researchers, academic partners, and the broader project team so that decisions about soils, planting, wildlife movement, screening, and infrastructure performance are informed by the best available knowledge.

The crossing represents more than a safe passage over a freeway. It is an effort to restore ecological continuity across the Santa Monica Mountains and create connected habitat for mountain lions and the many other species that move through this landscape.

The story of P-22 helped bring international attention to the consequences of habitat fragmentation. After crossing major freeways and making his home in Griffith Park, he became a symbol of both wildlife resilience and the urgent need for safer movement through the region.

The Wallis Annenberg Wildlife Crossing carries that legacy forward. It demonstrates how infrastructure can serve human mobility while also repairing ecological connections—offering a hopeful model for how design, science, and collaboration can help people and wildlife share the landscape.

The Wallis Annenberg Wildlife Crossing addresses a complex ecological challenge at an extraordinary scale. But explaining habitat connectivity, wildlife movement, and living infrastructure to a broad audience can be just as important as designing the crossing itself.

Rock imagined a different way to tell that story: through LEGO bricks. The familiar medium offered a playful, accessible way to translate a sophisticated landscape project into something people of all ages could understand and explore.

Created in collaboration with LEGO artist Martin Egemo, also known as TMX Brick Notes, the model reinterprets the Wildlife Crossing at miniature scale. Landscape, infrastructure, vegetation, and carefully selected wildlife minifigures work together to communicate how the real crossing reconnects habitat divided by the 101 Freeway.

The project was developed by Rock while at Living Habitats as an entry for the 2023 LEGO Ideas® competition.

By reducing an enormous piece of ecological infrastructure to something tactile and familiar, the model makes the underlying idea easier to grasp: landscapes can be reconnected, and infrastructure can be designed for more than one species.

Although the competition has concluded, the project remains an example of how design communication can become part of the design process itself—using curiosity, creativity, and play to build understanding around serious environmental challenges.