Wildlife Crossing - Wildlife-vehicle Collisions

Wildlife-vehicle Collisions

In addition to conservation concerns, wildlife-vehicle collisions have a significant cost for human populations because collisions damage property and injure and kill passengers and drivers (Clevenger et al. 2001). Bruinderink & Hazebroek (1996) estimated the number of collisions with ungulates in traffic in Europe at 507,000 per year, resulting in 300 people killed, 30,000 injured, and property damage exceeding $1 billion. In parallel, 1.5 million traffic accidents involving deer in the United States cause an estimated $1.1 billion in vehicle damage each year (Donaldson 2005).

The conservation issues associated with roads (wildlife mortality and habitat fragmentation) coupled with the substantial human and economic costs resulting from wildlife-vehicle collisions have caused scientists, engineers, and transportation authorities to consider a number of mitigation tools for reducing the conflict between roads and wildlife. Of the currently available options, structures known as wildlife crossings have been the most successful at reducing both habitat fragmentation and wildlife-vehicle collisions caused by roads (Knapp et al. 2004, Clevenger, 2006).

Wildlife crossings are structural passages beneath or above roadways that are designed to facilitate safe wildlife movement across roadways (Donaldson 2005). In recent years, conservation biologists and wildlife managers have advocated wildlife crossings coupled with roadside fencing as a way to increase road permeability and habitat connectivity while decreasing wildlife-vehicle collisions. Wildlife crossing is the umbrella term encompassing underpasses, overpasses, ecoducts, green bridges, amphibian/small mammal tunnels, and wildlife viaducts (Bank et al. 2002). All of these structures are designed to provide semi-natural corridors above and below roads so that animals can safely cross without endangering themselves and motorists.