Experts are finding that highways create significant barriers to the natural interconnection among animals within a large region. Busy highways can split wildlife into small, fragmented populations that are much more vulnerable to population fluctuations because they've lost their ability to roam and interact. Society hasn't come to grips with the ecological effects of this road system, but it is beginning to. Some experts suggest examining the problem from an animal's viewpoint. On a typical four-lane highway carrying 20,000 vehicles a day, a car or truck would pass every 4 seconds.
Roads effectively can become very solid barriers to a lot of species of wildlife.
At Banff National Park in Alberta, Canada, ecologists are working to mitigate the impact of widening the Trans-Canada Highway to four lanes. They used a combination of fencing, wildlife underpasses, and overpasses, and recorded a 96 percent reduction in road kill of elk and deer. A Lot to Get Used to Grizzly bears, wolves, and cougars regularly use the underpasses. He says wolves and grizzly bears are very wary animals. Then it takes them time to get up the courage to go through them.