Roadkill: roadside tunnels reduce human and critter deaths

By: Drivers.com staff

Date: Monday, 04. June 2007

When considering the hazards of driving, most drivers think in terms of collisions with other traffic or with pedestrians. Few people, particularly in urban areas, consider the possibility of coming into contact with animals, particularly the larger species such as deer, moose, bears, and wolves.

Yet in the United States alone, more than 200 motorists are killed and thousands more injured in animal-vehicle collisions. The insurance industry estimates that the annual cost to society for these accidents is $200 million. On average, hitting a deer costs about $2,000 in vehicle repairs.

Fatalities, personal injuries, and repairs are only part of the story, however. Millions of smaller vertebrates, some of them on the endangered species list, are killed every year. In the U.S., for example, roadkill has helped to reduce the population of an endangered cat-the ocelot-to about 80 animals. Grizzly bears, the lynx, and some rare frogs and toads are similarly threatened.

Highway construction not only eats up large tracts of land formerly occupied by wild animals, the roads themselves fragment the landscape, dividing wildlife populations into increasingly smaller and more isolated units. This fragmentation may cut off animals from their nesting or mating sites and even lead to inbreeding and genetic defects.

"Forest fragmentation threatens all wildlife species that have to cross roads to meet their biological needs," says biologist Bill Ruediger, of the U.S. Forestry Service. "They're at risk because of their small populations, low reproduction rates, and large-even huge-home ranges."

Aware of the seriousness of this problem, some of the more enlightened jurisdictions in several countries are taking action to help cut down on the annual slaughter by providing systems of fences and tunnels along major highways. Information on these projects is provided on the U.S. Federal Highway Administration's well-illustrated web site.

In the Netherlands, for example, the national Ministry of Transport has been working for several years to build and improve a system of fences and tunnels to protect the local badger population, 20 per cent of which was being killed on the roads every year. Since they were installed, infrared sensors and other tracking devices demonstrate that badgers are using the tunnels every night, as are foxes, rabbits, and hedgehogs.

Tunnels also provide a safe haven for slower-moving species, such as turtles, that are particularly vulnerable to roadkill.

In Amherst, Massachusetts, USA, volunteers with buckets used to turn out every spring to carry migrating salamanders across busy Henry Street. Now, as the result of a truly international effort, the salamanders are funneled through two 200-foot tunnels. Funding for the project was provided by the British Fauna and Flora Preservation Society and ACO Polymer in Germany. Amherst's Department of Public Works, the University of Massachusetts, the state Audubon Society, a local conservation group, and residents of Amherst then joined forces to make the project happen.

Short fences were built to guide the salamanders into the tunnels, and the tunnels themselves are slotted to let in light and provide the damp conditions the creatures need.

Also in the USA, Florida has installed highway underpasses for black bears and panthers, and research has shown that a recent crossing for bears on State Route 46 is also being used by bobcats, gray foxes, and whitetail deer.

And a highly successful system of underpasses and overpasses along the well-traveled Trans-Canada Highway in Alberta's Banff National Park has cut the roadkill rate of hoofed animals such as deer, elk, and moose by 96 per cent.