Wildlife bridges and tunnels reducing wildlife death toll on the roads

Creating safe places for wildlife to cross

December 2010: Design features such as overpasses keep drivers moving safely on our roads, letting cars pass in different directions without interacting with other cars or trains. Allowing wildlife to move from one side of the road to the other without encountering vehicle traffic is a challenge for transport planners and wildlife managers. As transport networks continue to expand, a similar solution may help avoid wildlife-vehicle collisions.

A new study rates the effectiveness of highway underpasses for wildlife, and found that a notable number of creatures were saved - and that fewer vehicles were damaged.


Coliisions can be deadly for animals and humans
Collisions between wildlife and vehicles can cause substantial damage to vehicles as well as injure - or sometimes kill - people. As for wildlife, a deadly road can affect the viability of small populations of animals.

A new route planned for U.S. Highway 64 in Washington County, North Carolina, gave researchers the opportunity to document wildlife activity both before and after the road was built. The new route cut through a forested and agricultural area, bringing together cars and resident animals such as black bears, red wolves, and white-tailed deer. Part of the highway construction included three underpasses with fencing running alongside the roadways near each underpass to ‘funnel' the animals through.

New 'animal-safe' highway saw road deaths down by nearly 60 per cent
With the use of multiple cameras and surveys of animal tracks, researchers counted wildlife activity both in the planning and construction stages of the highway and after it was completed and open to traffic. Before road construction, the cameras captured 242 instances of deer passing through the area where the underpasses would be. During a 13-month period after construction, 2,433 photographs of various animals, primarily deer, but also bears, raccoons, and domestic dogs and cats, were taken as they used the underpasses. Animal deaths from vehicle collisions were counted as well.

When compared with reports from adjacent sections the highway, the new section of road experienced a 58 per cent reduction in wildlife mortality. This suggested a favourable cost-benefit analysis for building the underpasses.

Improvements to further reduce wildlife-vehicle collisions include continuous fencing along roads rather than small sections, higher fences, and fences dug into the ground to prevent smaller animals from going underneath. Drainage culverts placed at more frequent intervals, rather than larger underpasses built farther apart, could provide a more economical way to allow animals to pass under the road.

http://www.wildlifeextra.com/go/news/roads-wildlife2010.html