Keeping Hoofs Off Hoods

Phase 2, the two-mile stretch from Keechelus Dam to the Stampede Pass Interchange, began in the summer of 2015. Completion is projected for 2019. Photos courtesy WSDOT.

Costs and benefits

The cost of collisions is staggering. A 2008 Federal Highway Administration report to Congress that estimated the tragic loss of human life also calculated the annual financial cost at $8.4 billion. Insurance companies track collisions when damage is reported: 1. 3 million claims for the year ending June 30, 2016, according to a State Farm Insurance study.

Wildlife inevitably pay far more dearly. The 2008 report to Congress found that road mortality is a major threat to the survival of 21 species listed under the U.S. Endangered Species Act.

By far the most ecologically comprehensive mitigation project I'm aware of in North America and likely the world.

—TONY CLEVENGER, SENIOR WILDLIFE RESEARCH SCIENTIST, WESTERN TRANSPORTATION INSTITUTE, ON THE 1-90 SNOQUALMIE PASS PROJECT

Often, animals don't even try to cross roads. That means they are cut off from whatever habitat lies on the other side. This landscape fragmentation has had long-term impacts for broad-ranging animals such as wolves and bears. A new discipline called landscape ecology, also known as conservation biology, took shape in the 1980s and early 1990s. It holds that fragmented habitat, the so-called island effect, reduces genetic diversity of species. The smaller the island of habitat, the greater the risk the species will disappear from that island — and potentially altogether. We have been, one road ecologist points out, losing species like crazy. Roads alone are not to blame, but they're part of that problem.

The first bridges planned with wildlife in mind were constructed in the 1970s in New Jersey and Utah. Then a segment of Interstate 75 in Florida called Alligator Alley was modified with 23 underpasses and widened bridges, coupled with exclusionary fences, to keep critters off the road. The goal was to allow gators and panthers, the official animal of Florida, safe passage without getting squashed.

Then came Canada's flagship Banff National Park. Six overpasses and 38 underpasses have been woven into the Trans-Canada Highway as it has been expanded from two lanes to four lanes since 1982. Bordering fences, sturdy and tall, funnel animals to the crossings along a 50-mile segment. Similar work is now continuing across the Continental Divide at Kicking Horse Pass and into Yoho National Park.

In continuous monitoring since 1996, these underpasses and overpasses have reduced collisions by more than 80 percent altogether for large mammals, including bears and wolves, and by more than 95 percent for ungulates like elk, moose, and deer, according to the Western Transportation Institute's Clevenger.

Research has also revealed the passage preferences of species.

"We learned that black bears and cougars liked the smaller structure with more cover and less light, while grizzly bears, wolves, and ungulates preferred the larger, open structures," says Clevenger.

New technological tools have allowed Clevenger and other scientific detectives to document the long-term population-level benefits that accrue from increased gene flow between populations. Clevenger jokes that these structures have been called the "tunnels of love." The background vision helping drive the work in Banff is an unimpeded wildlife corridor from Yellowstone to the Yukon, referred to as Y2Y.

Strapped for money, state departments of transportation have resisted adapting roads to wildlife. The usual trigger has been a highway widening or an egregious example of roadkill. In some states, as many as 90 percent of wildlife crashes involve deer. The State Farm Insurance statistics for last year showed Pennsylvania leading the nation with 133,187 claims, followed by New York with 70,405, then Ohio at 62,874.

Road ecologists say that reducing collisions alone makes wildlife-crossing structures pay for themselves. The 2008 report to Congress said an overpass along a road segment that has 3.2 deer-vehicle collisions per kilometer annually would generate economic benefits considerably in excess of its lifetime capital costs.

In some high-profile intersections of hoofs and hoods, the payoff can be quicker, just two to four years, says Fraser Shilling, codirector of the Road Ecology Center at the University of California–Davis. "They pay for themselves pretty easily," he says.

Driving down the Trans-Canada Highway in Banff National Park, you can spot a total of 44 wildlife crossings: six overpasses and 38 underpasses. Since the park's first overpass opened in 1995, the number of vehicle collisions with large animals has decreased by almost 80 percent. Photo by Adam Ford.

Adjacent land use matters

Land use that abuts crossing structures matters entirely. "You don't want to spend all this money building a wildlife over-crossing and have a Walmart next to it," says Patricia Garvey-Darda, the wildlife biologist for the U.S. Forest Service on the Snoqualmie Pass project. She describes crucial work that began in 1997 amidst fears of losing old-growth forest and the spotted owl. The problem dates back to the late 1880s, when the federal government, seeking to encourage growth of railroads, gave them a checkerboard quilt of lands from the public domain. Those parcels near Snoqualmie Pass became tree plantations, planted thickly with Douglas fir by the Plum Creek Timber Co. Late in the 20th century, the company also began selling the land to real estate developers. Neither was good for wildlife.

The problem was finally solved with a massive land exchange in 1998 that put management of 85,000 acres of formerly private land in the hands of the Okanogan-Wenatchee National Forest. Garvey- Darda says that swap took a lot of work and strong partnerships.

The Forest Service mission of maintaining biological diversity was integral to the Snoqualmie designs. Because the highway crosses the agency's land, it was at the table when the review process began in 1999. An interdisciplinary team of eight state and federal agencies defined a purpose and need that included ecological connectivity. "That was a really big deal, setting the ground rules," says Garvey-Darda.

The WSDOT team was the first to have outside participation. This led to tasking a technical advisory subcommittee consisting of hydrologists and biologists from different agencies to identify locations and develop science-based performance criteria for investments in ecological connectivity. They had to figure out not just what was adequate, but also what was best.

"The process was quite visionary and progressive at the time. As a consequence, it was not always popular," says Jason Smith, environmental science and planning practice lead at the Jacobs Engineering Group's Pacific Northwest region.

The best proposals for measures for habitat connectivity became part of the record of decision signed in 2008. To do less than that requires a supplemental review under the National Environmental Policy Act. "And nobody wants to do that," says Garvey-Darda. "To me, this is the model for how it should be done."

Collaboration was paramount, says Mark Norman, biology program manager for WSDOT. "It's critical that you understand the missions of each other's agencies, and that you understand each other's disciplines." Garvey-Darda concurs. "Once we understood each other it was a whole lot easier to identify the 'win-win' solutions."

In Arizona and Virginia, too

Along the Eastern Seaboard, public lands are more scarce, species somewhat different, and wildlife structures still rare. North Carolina has crossing structures for black bears and also deer, and Georgia has been looking into them.

Virginia will soon erect fencing to guide deer to two underpasses in areas where seven to 11 collisions occur per year. Camera monitoring will be used to determine how effective it is. Driving the effort is collision avoidance, but smaller species — like turtles — can benefit, too.

So far, wildlife mitigation has been a lowerpriority issue for the Virginia Department of Transportation, says Bridget Donaldson, senior research scientist for the Virginia Transportation Research Council. Nor are there endangered species listings to spur investments. "We really need to cross boundaries and get other people involved," she says. "We need to speak more with the engineers and planners and maybe some of the administrators at DOTs, just to bring each other up to speed. We need to know their challenges, and they need to know our needs."

On the other side of the country, Arizona's efforts were prompted first by elk collisions. It began making highways permeable to wildlife in 2000. Today, they can cross in 17 places. Drive from Las Vegas across the Colorado River and into Arizona, and you soon pass under the first of three bridges built for desert bighorn sheep.

The Arizona Game and Fish Department's Jeff Gagnon put radio-collar telemetric devices on desert sheep in 2004 to determine where they crossed U. S. Highway 93 between sparsely vegetated public lands. "The technology really helps answer a lot of this stuff," he says. Monitoring has continued to evaluate effectiveness of the structures. In time, the sheep began using the overpasses. "We have probably collared 500 elk, 300 pronghorn, a few hundred deer, plus desert sheep," Gagnon says.

The Tucson area delivers the most striking case study of the intricate intersection of roads, wildlife, and land-use planning. Pima County has rich biological diversity: deer, javelina, coati, the Sonoran Desert turtle, and Gila monsters, among others. The desert city is ringed by high mountains, called sky islands, that serve as refuges for different species.

Banff National Park signs alert guests to wildlife corridors. Photo by Adam Ford.

Oracle Road, also called State Highway 77, passes through the town of Oro Valley, 17 miles northeast of downtown Tucson. The road also crosses a habitat link between the sky islands. An important transportation ballot initiative preserved that connectivity.

In 2006, Pima County voters handily approved a half-cent sales tax to produce $1.2 billion for expanded bus service, wider roads, and new bike paths. A key provision for the 20-year plan was a $45 million carve-out for wildlife permeability. Of that, $11 million went to the Oracle Road project.

In Tucson, as at Snoqualmie Pass, partnerships were crucial. "It's pretty complicated in the number of jurisdictions that had to be on the same page," says Carolyn Campbell, executive director of the Coalition for Sonoran Desert Protection. She identifies the Arizona State Land Department as a major player. The agency manages 9.2 million acres in the state.

Sarah More, FAICP, former planning director for Oro Valley, says a land-use plan for 9,000 acres near the Oracle Road site shifted density to open up lands for wildlife. Then the recession idled the road work.

"That's OK," says More. "As planners, we have to be really patient and looking forward into the future, knowing you have set the framework far into the future and hope people stick to the plan."

An earlier planning document helped set the stage. Completed in 2002, the Sonoran Desert Conservation Plan assessed critical habitats and biological corridors, riparian areas, mountain parks, historical and cultural preservation, and ranch conservation. "That came from the science community without regard for political jurisdictions," says Sherry Ruther, environmental planning manager in Pima County's Office of Sustainability and Conservation. "As with any community, there's a lot of bricks in the foundation for things that end up being much grander in scale."

No endangered species listings drove funding directly to the wildlife permeability work on Oracle Road; instead, as at Snoqualmie Pass, the wildlife work came paired with a highway widening. "It's a lot more efficient and economical to do something in partnership with a project that [already] is going to happen," says Ruther. She calls it a "moment of grand opportunity."

Planners need to understand that wildlife overpasses represent the "smallest end of the funnel," Ruther says. "It also matters what happens 100 feet from where the crossing structure is. It matters what happens a mile from [there]. That's where land use becomes important. Without providing habitat, you have basically built a bridge to nowhere."

Put another way by Banff's Tony Clevenger, a wildlife overpass is just a small solution to a large landscape problem. Since Clevenger began his study, Banff's structures have inspired worldwide mitigation of what he calls linear landscape disturbances.

In 2016, new wildlife bridges were constructed in Colorado and Nevada, and more are being planned in Utah near Salt Lake City and in Wyoming's Jackson Hole. In California, a crossing of U.S. Highway 101 in the Santa Monica Mountains near Los Angeles is being planned to accommodate movement of mountain lions, also called panthers and cougars. The National Wildlife Federation is reportedly trying to raise $50 to $60 million to build the structure that would become the largest wildlife crossing in an urban area in the world.

Wildlife bridges and underpasses are being built because science has proven their effectiveness, says Rob Ament, road ecology program manager for the Western Transportation Institute in Bozeman, Montana. "The science keeps confirming what everybody suspected: In highly fragmented landscapes, maintaining connections is important if we want to coexist on that landscape with species," he says.

What needs to change, he adds, is that wildlife permeability needs to become a systematic part of all road construction instead of a case-by-case consideration. "Our roads are systematic, but our mitigation is not," he says.

Caught on Candid Camera

Wildlife crossings offer unique opportunities to study animal behavior, particularly via trail cameras. Along I-90's Snoqualmie Pass, stacks of grass, fireweed, and other plants — called hay piles by researchers — are being monitored. They're put there by pikas, tiny mammals especially sensitive to precipitation levels. By keeping tabs on the location and size of these piles, researchers can identify how climate change impacts the pika population.

To learn more about how crossing structures may filter use by male and female bears, the Western Transportation Institute at Montana State University collected bear hair samples in Banff National Park. They discovered that grizzlies, particularly family groups, prefer using open, vegetation-covered overpasses. Black bears (bottom row) are less selective of crossing structure types; they use a wide range of underpass designs and occasionally overpasses.

Allen Best writes about energy, water, and transportation from Denver. He is a frequent contributor to Planning magazine.

Resources

ARC (Animal Road Crossing) started as an interdisciplinary design competition in 2010. Today, through new methods and materials, ARC Solutions continues to answer the question, "How can design save wildlife and wild places?" arc-solutions.org

In the past 17 years, more than 150,000 of Banff National Park's animals have been granted safe passage along the Trans-Canadian Highway. In this video, look at the fencing, overpasses, and underpasses that make it all possible — through the eyes of one of those animals. youtu.be/qgLF37te2N8

Every spring, mule deer walk 150 miles across western Wyoming. National Geographic investigates the environmental obstacles and modern-day challenges — highways and fences — they encounter. youtube.com/watch?v=BIAyb-1uwTg