A new relationship with animals, nature and each other.

Bridge Over Troubled Highways

A wildlife overpass competition puts focus on human-animal cohabitation

By Leda Marritz

Hopefully you have never had the misfortune of trying to cross a highway on foot. It’s a terrifying experience. As well as trucks careening at you at 80 miles an hour, you have to negotiate medians, planters and grade variations. Highways are not designed to be crossed, and most of us never have to. But if you’re an animal on a perilous migration, and a highway is what stands between you and survival, well — you’ll try it.

One such treacherous highway for wildlife is I-70, which winds through the Rocky Mountains. But now local animals may be about to get their own overpass, courtesy of a new design competition.

The International Wildlife Crossing Infrastructure Design Competition (ARC) inviting design teams to create an innovative, safe, cost-effective and “ecologically responsive” wildlife crossing along a section of the I-70 just west of the Vail Pass in Colorado. It is the first design competition of its kind in North America to focus on the integration of wildlife migratory patterns in to bridge and road design.

The vegetated wildlife overpass will serve as a critical artery between the two sides of contiguous wildlife habitat that I-70 bisects for animals migrating through the Rocky Mountains.

Thoughtfully designed and executed wildlife crossings are an effective means of protecting animal populations whose migratory or foraging patterns put them in direct conflict with humans and vehicles on roads and highways. Until recently these crossings have been created mostly for amphibians and small mammals. This undertaking, by contrast, must be suitable for a variety of species, from the relatively small snowshoe hare to large animals like elk, moose, black bear, coyote, and lynx.

More than one million animals are killed on roads in the United States every day, making it the leading cause of vertebrate deaths in the U.S., and as a proportion of total vehicle accidents this number is growing. According to a 2008 study, vehicle collisions (also called road mortality) are a leading risk factor for 21 federally threatened species.

ARC considered 25 sites in 16 different states as potential locations for the competition. Each was evaluated on factors that included ecological importance, number and frequency of vehicle-wildlife collisions, charismatic nature of the site and its wildlife, willingness of the local Department of Transportation to work with ARC, and existing plans for a wildlife structure under new infrastructure funding. The winning section of I-70 met all the criteria. The timing is perhaps especially relevant for this site, as the local agencies are considering expanding I-70 from four lanes to six.

Design competitions are an effective way to raise international support and interest in particular topics while producing a unique deliverable. These competitions often focus on Big Ideas like rejuvenating blighted urban areas or improving neighborhood access to public transportation and parks, making ARC’s goal — to  “raise international awareness of a need to better reconcile the construction and maintenance of road networks with wildlife movement” — rather unusual.

The competing design teams won’t be limited to landscape architects and architects — engineers, ecologists, and other experts will also contribute.  An interdisciplinary approach will be critical to meeting the many project requirements, including innovative design, sustainable materials, and optimal functionality from both an ecological and engineering standpoint.

Submissions will be on display starting in January 2011 at the Transportation Research Board Annual Conference in Washington, D.C., and the winning design will be announced thereafter. The Colorado Department of Transportation (CDOT) will then have the opportunity to enter in to a contract with the winning team to complete the structure.

As highways unfurl like concrete banners across the country, the march of vehicles and buildings that accompany them can feel unstoppable — a kind of strange Manifest Destiny 2.0. Their wake of fractured ecosystems is increasingly serious, especially as global warming alters the balance of food resources and available habitat. Wildlife overpasses are one tool to counteract the consequences of aggressive development and expansion. Their integration is slow moving and uncertain, and undoubtedly they are not as bold and overarching a solution as some of us would like. In the end, however, their practicality may end up being the critical factor to their acceptance and success.