A moose uses an overpass built by CDOT in an effort to reduce road kill on Colorado highways. 

(Courtesy CDOT)

Colorado drivers killed nearly 7,000 wild animals last year, according to a road kill survey from state Department of Transportation. But one stretch of highway saw a huge decline.

On Highway 9 near Silverthorne, collisions have dropped almost 90 percent after CDOT built bridges and tunnels to help keep animals away from traffic and get them across roads safely. The structures were placed where animals naturally cross the highway.

The project was completed in 2015 but CDOT plans to collect data on the Highway 9 project until 2020.

“We had seen more than 30 crashes per year with wildlife on this corridor,” CDOT’s Regional Communications Manager Lisa Schwantes said. “After the implementation of the first phase of this project, there were only three documented crashes.”

For this project, CDOT built two bridges, five tunnels and 10 miles of fencing, making it the most ambitious project of its kind and most expensive at $40 million.

“Other projects are typically just one overpass or one underpass and some projects are just fencing, so we’re looking at a few million versus 40 [million],” Schwantes said.

So far CDOT hasn’t received any criticism over the construction of these bridges and tunnels, Schwantes says.

“I think Coloradans have a love for the outdoors and for our wildlife. And they appreciate that we’re trying to make the highway safer,” Schwantes said.

With wildlife collisions up by about 50 percent across the state in the last four years, more projects like Highway 9 are set to launch. Projects are underway in Montrose, Durango, Salida and Pagosa Springs.

CPR News' Xandra McMahon contributed to this report.