Vail Pass Wildlife Bridge

A concept to reconnect wildlife habitat and save human lives
Aerial view of Vail Pass

Aerial view of I-70 just west of the Vail Pass summit, near where the wildlife bridge is proposed. Lower Black Lake is in the foreground; East Vail is barely visible in the distance. Photo by Sloan Shoemaker.

In cooperation with Rocky Mountain Wild and our Colorado Congressional representatives, we’re working to support the Colorado Department of Transportation’s effort to build a vegetated wildlife overpass on I-70 east of Vail Pass. This wildlife-only bridge would reconnect fragmented habitat, save human lives and provide a model for wildlife protection nationwide.

I-70 is often called the Berlin Wall to Colorado’s wildlife, because it presents an almost impassable barrier to animals migrating between the southern and northern parts of the state. There are several points where wildlife can go under the highway, but they’re not always located where animals traditionally want to cross. Plus, some species, notably lynx and moose, prefer to stay above ground.

The Colorado Department of Transportation has a natural interest in the subject, given that collisions with wildlife pose a significant danger for highway users. Nationwide, vehicle-animal collisions are estimated to cause 210 human fatalities, 29,000 human injuries and $8 billion in property damage annually.

In 2006, with our help, CDOT received a federal appropriation of $420,000 to perform preliminary engineering and environmental assessments of the West Vail Pass wildlife bridge. With that study complete, the project is now ready for the design phase.

We and our partners homed in on the West Vail Pass location early on because it’s a choke point along a critical wildlife migration corridor (two reintroduced lynx have been killed by vehicles there in recent years), and reconnecting the habitat on both sides of the interstate will help ensure continued interbreeding and genetic diversity. Additionally, it’s a location where animal access to the bridge will never be cut off, thanks to both sides of the highway being Forest Service property. Our hope is that an overpass in this high-profile location will create public support for many more structures throughout the state.

The big hurdle to constructing such a bridge, of course, is money. A structure based on designs pioneered in Canada’s Banff National Park, configured to span a potential six lanes of I-70, could cost as much as $12 million. To help reduce the cost, the most recent design would span only one lane in a location where the other lane is elevated for several hundred meters. Given the current government belt-tightening, it’s likely to be a while before we see that appropriation from Congress.