Wildlife crossings: Building safer roadways for humans and animals
By Sarah Jaclyn Hertrick, MPA
Wildlife overpass in Banff National Park, Canada. Photo from Canadian Geographic, by Gloria Dickie.
It was 6:30 pm, the sun was setting, and I was making my way through the city streets when much to my surprise, I looked out the car window and saw deer. To clarify, this wasn’t a wooded area where you would expect to spot deer, but rather a commercial business complex, at a particularly busy intersection in the middle of the city.
Wild critters rely on the land they roam for sustenance and shelter so, as our built environment continues to expand, there are detrimental consequences for wildlife populations. Roads, railways, pipelines, canals, and power lines contribute to habitat fragmentation. The massive US road system ecologically impacts at least one-fifth country’s land area.
The bustling traffic of city streets and highways does not stop animals from crossing roadways. If not properly handled, such road crossings can lead to fatalities among motorists and wildlife. With increased urbanization, wildlife-vehicle collisions have increased by 50 percent over the most recent 15 year period. An estimated one to two million large animals are killed by drivers every year.
These crashes are also expensive. Deer-car collisions cost an average of $8,190, an elk-vehicle collision is about $25,319, and a moose-vehicle collision is $44,546 when taking into consideration human injuries and death, towing, vehicle repair, investigations by local authorities, and carcass disposal.
There is one solution that has been proven effective in reducing the amount of wildlife-vehicle collisions on roadways by 80-90%: wildlife under-and overpasses. Studies have shown that in addition to saving lives, the benefits derived from wildlife crossings outweighs the costs of construction and maintenance.
European nations such as France, Germany, the Netherlands, and Switzerland have employed crossing structures for decades to reduce the impacts road-ways have on wildlife populations. The success of these solutions in reducing the negative impacts of urban sprawl has led to the increased adoption of similar infrastructure in the United States. In 2019, Congress introduced the Wildlife Corridors Conservation Act which would establish a National Wildlife Corridors System to “provide protection and restoration of native species and their habitat in the United States that have been diminished by habitat loss and fragmentation” on federal public lands. Garnering bipartisan support, the legislation passed in the House of Representatives as a part of the Moving Forward Act.
The Need for Wildlife Crossings in the Triangle
“It is a mistake to draw a distinction between urban and rural areas. We don’t have that luxury anymore, as urban areas expand into wildlife areas and the U.S. becomes increasingly urbanized. We have local and migratory wildlife populations that utilize the urban habitat...if we write off our urban wildlife populations then we write off our wildlife populations completely.”
The human population isn’t the only one thriving in the Triangle. According to the N.C. Wildlife Resource Commission, Wake and Mecklenburg counties (home of the state’s largest cities), have deer herds with more than 45 animals per square mile.
Map of wildlife crossings in NC. Graphic from Wildlands Network.
To offset the growth of the deer populations, the Resource Commission has implemented several new mechanisms to increase the annual harvest. However, despite these efforts the collisions between vehicles and deer are “out of control” according to Resource Commission biologist, Greg Batts.
“In Wake County, there are just as many, if not more, deer killed by cars than hunters,” noting that 3,600 to 3,800 deer carcasses are removed from the highways around Raleigh each year. Comparatively, hunters kill on average 2,600 to 2,900 deer within Wake County’s borders.
Mitigation efforts are already underway throughout North Carolina with the construction of several wildlife crossings, one of which is right here in the Triangle at the New Hope Creek bridge on 15-501. The New Hope Creek underpass was built to reduce the risks of motorists and wildlife by providing a safe passage along the corridor.
Underpass in NC. Photo from Wildlands Network.
Habitat loss and rising human populations pose significant threats to wildlife. One of the most frequently cited ways of combating these crises is to re-establish habitat connectivity. By strategically building solutions in the form of overpasses and underpasses in our environment, we can take steps to reduce wildlife-vehicle collisions, conserve native wildlife, and improve public safety.
For more information and resources about wildlife crossings check out Prioritizing Wildlife Road Crossings in North Carolina and Wildlife Crossings: Rethinking Road Design to Improve Safety and Reconnect Habitat.
