One official calls Interstate 70 through Colorado’s Rockies “the Berlin Wall for wildlife.” Animals killed there include cougars, bears, moose, elk, two of the state’s reintroduced Canada lynx and Colorado’s first recorded wolf in over 70 years, who had wandered all the way from Yellowstone only to be struck by a car.
The amount and diversity of roadkill reflects the area’s value to wildlife and helped inspire a recent international competition to design a wildlife highway crossing over I-70 at Vail Pass.
Now, a newly formed coalition of engineers and conservationists, calling itself the Rocky Mountain Wildlife Bridge Company, wants to build the crossing. It envisions a revolutionary design to add to a growing number of highway wildlife crossings across the country. Each is changing the way we think about roads and promising big benefits for both motorists and wildlife.
The crossings reflect a national problem. The Federal Highway Administration estimates that wildlife-vehicle collisions cause $8 billion in damages annually, while the Insurance Institute for Highway Safety says that roughly 200 people are killed each year. The Humane Society of America estimates that over 1 million animals die on U.S. roads daily, including panthers, pelicans, grizzlies, elk and many others.
Fortunately, in a decades-long movement now gaining momentum, biologists, conservationists and engineers are collaborating to build safer roads. A successful example is U.S. 93 between Missoula and Flathead Lake in northwest Montana. Before a planned highway expansion, tribes, conservationists and state agencies partnered to include dozens of wildlife crossings along the 60-mile stretch. Most are over-sized culverts with “wing fences” that guide wildlife toward them. Remote cameras have now recorded thousands of animals using the crossings, including deer, bears, otters, owls, turkeys, and more. Footage shows mother deer and bears training their young to use the crossings, and preliminary evidence suggests considerable declines in collisions.
In Idaho, where 5,000 animal-vehicle collisions were reported in 2012 and damages cost an estimated half million dollars annually, transportation and wildlife agencies teamed up on several wildlife underpasses. Cameras show animals using one near Boise, and officials estimate 80 percent of deer and elk bound for the highway will ultimately detour into the underpass.
In California, fences guide endangered desert tortoises toward culverts beneath Route 58, which slices across the Mojave Desert. Researchers say it has decreased wildlife mortality over 90 percent in just four years. Back in Colorado, many motorists winding through Glenwood Canyon on I-70 are unaware that the road’s redesign in the 1990s included features to protect bighorn sheep.
In the 1980s, Canada’s Banff National Park set the standard for North American wildlife crossings, constructing 22 underpasses and two overpasses where a highway bisects the park. Research indicates grizzlies, wolves, elk and other animals have used the corridors 240,000 times, resulting in an 80 percent decline in collisions. Researchers even documented mothers teaching their young how to negotiate the routes.
Increasingly, motorists aid the effort. In 2009, savvy researchers at the University of California at Davis realized that the millions of GPS-equipped phones and cars Americans now own could provide unprecedented data on collision patterns. They created the California Roadkill Observation System, the first statewide roadkill reporting website. Drivers have uploaded data on thousands of wildlife collisions, including GPS coordinates, date, time and species, and a recent app now invites bicyclists to participate. In 2012, Idaho created a similar system.
In Washington, state and federal agencies, conservationists and the University of Montana created the “I-90 Wildlife Watch” website. Drivers can use an interactive map to report both living and dead animals on a busy stretch near Snoqualmie Pass due for upgrades. Users report becoming hooked, and the data will help agencies design and place new wildlife crossings. In February, the agencies announced a scholarship for high school students to help with design.
All of this is important work. The wildlife killed on our roads includes males seeking mates, mothers of vulnerable young, amphibians migrating to breeding grounds. Their deaths come at a time when extinctions are soaring. Meanwhile, climate change is causing animal migrations, not just north and south, but across valleys, up and down mountains, to wherever the good food and weather is shifting. As the migrations increase, safe wildlife crossings help prevent populations from becoming fragmented or isolated. They also preserve the integrity of our protected places.
For instance, the proposed Vail Pass crossing will link the Eagles Nest Wilderness and the Holy Cross Wilderness on the White River National Forest. Crossings in Montana, Washington and elsewhere also link similar lands, improving their function for genetic exchange and food variability.
Of course, the crossings also make roads safer for people, saving untold numbers of lives and damages every year.
Tim Lydon is a contributor to Writers on the Range, a service of High Country News (hcn.org). He writes in south-central Alaska.