By Allen Best
Along Highway 160 in southwestern Colorado, the movement of deer and elk mark the changing seasons. In winter, they browse amid the plateaus, canyons and prairies south of the highway. Come May, the herds cross the highway, following the receding snow line northward into the lofty San Juan Mountains. Many don't make it.
Each day, the highway carries 20,000 to 30,000 vehicles between Durango, a resort and college town, and the burgeoning bedroom community of Bayfield, 15 miles to the east. Vehicle collisions with wildlife occur frequently, nearly always killing the animals and sometimes people. In the bloodiest one-mile strip, wildlife collisions account for 70 percent of all accidents, compared to 20 percent in other highway segments of the region. "The average costs associated with a deer-vehicle collision are about $6,600. This includes property damage and also costs associated with the occasional human injury and human fatality," says Marcel Huisjer, a research ecologist with the Western Transportation Institute in Bozeman, Montana. "The costs for the average elk- or moose-vehicle collision are higher at $17,500 and $30,800 respectively." Nationwide, wildlife collisions cost $8 billion a year and kill about 200 people—and countless wild animals.
"Wildlife needs to move around—sometimes hundreds of miles in a year—to find food, shelter and mates," says Trisha White, director of Defenders of Wildlife's Habitat and Highways Campaign. "When we build highways through their habitat, we shouldn't be surprised when cars and animals collide."
Highway engineers and wildlife biologists have puzzled for decades about how to keep deer hooves and car hoods apart. Recently, the Colorado Department of Transportation has turned to technology previously used at prisons, military bases and airports to detect intruders in unauthorized areas. The technology—specialized cables—can detect the electromagnetic fields given off by any living creature the size of a cat or larger. Now on Highway 160, when a large animal moves across the cable buried about nine inches beneath the ground, it triggers 12 warning signs in the one-mile corridor, alerting motorists that there's a large animal within 30 feet of the pavement.
Research collected since the cable was installed in October 2008 suggests the warnings have slowed drivers and made them more alert. That's the goal. "We are hoping to reduce accidents, but we also want to see if we can change driver behavior," says Mike McVaugh, a traffic and safety engineer with the Colorado Department of Transportation.
In other states and in Canada, wildlife crossings and fencing have been shown to reduce wildlife-vehicle collisions by at least 80 percent. Fences along highways that funnel animals to highway underpasses have proved highly effective. The price tag for such projects can be in the millions of dollars, however. That cost is justified if a road section had at least 5.1 deer-vehicle collisions per mile before the mitigation measures were put in place, says Huijser.
Elsewhere in Colorado, Defenders persuaded state officials to build two wildlife underpasses southwest of Denver using federal stimulus money. More are planned. These strategically placed underpasses and fencing will allow deer, elk, bears, mountain lions, imperiled Canada lynx and other animals to travel safely under the highway to find the food, mates and quality habitat they need to survive.
"By making smart investments in wildlife crossings now, we will save millions of dollars each year, boost our local economies by creating jobs and, most importantly, save lives," says White.
As the effects of climate change become more challenging, it will become even more important for species that are being driven to higher elevations to be able to travel safely through the landscape.
And if the new surveillance technology works on Colorado's Highway 160, there could be a new tool to help critters safely get to the other side of the road while keeping people on their merry way.
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