DOUGLAS COUNTY, Colo. — After years of research, planning and construction to establish a new wildlife crossing in Colorado, the first signs of success are always something special for those behind the project.
It might be a trail camera's photo of a deer and her fawn. It might be a coyote paw print in the mud.
But it's really much, much more than that.
"When you see them go up, and when you see them work, and you start to get the (trail camera) pictures back, it just puts a huge smile on your face," Chuck Attardo, Colorado Department of Transportation's (CDOT) I-25 South Corridor environmental project manager, explained in mid-June. "To capitalize on this momentum that's been occurring for about the last five years and to get some of these things built and to see the success — it just makes us giddy."
As he stood under a new wildlife underpass built as part of the I-25 South Gap Project in Douglas County, his eyes lit up and his hands traced animal tracks in the mud.
He pointed to an elk hoof print, one of dozens printed into the wet ground, quietly saying, "Right there."
“CDOT has been working with CPW (Colorado Parks and Wildlife) and other partners to do these things for a long time," he said. "But we haven't done a great job getting ahead of it until now. We're starting to get a handle on it. And the reason why the pendulum is starting to swing in our direction is there's been a ton of momentum, both at the state and federal level.”
In recent years, wildlife crossing success stories have grown louder around the country, and CDOT is routinely collaborating with other western states to share ideas, Attardo said.
CDOT has built more than 40 wildlife underpasses and three overpasses, with more planned using state and federal dollars. Those crossings, paired with long stretches of wildlife fencing to funnel the animals to the safe passageway, have made an enormous impact: Reductions in wildlife-involved crashes hover around 90% in most cases.
“We’re seeing that because of the backing from our leaders here in Colorado and at the federal level... we are ahead of other states in the partnerships we can form and the amount of work we can get done in Colorado with building more of these," Attardo said. "Not just talking about it, but actually building more of these systems.”
Watch Denver7's in-depth coverage on wildlife crossings across the state below.
Wildlife crossings' 'significant' impact on driver, animal safety
While many wild animals die when they are hit by a driver, almost all of these crashes — an estimated 95.4% — end with no injury to people, according to the U.S. Federal Highway Administration. But in cases that involve sizable wildlife like elk or moose, the likelihood of human injury increases.
Every year, about 200 people die in the United States from these types of crashes, and an average of 26,000 people are injured.
In Colorado, drivers and CDOT report about 4,000 wildlife-involved crashes every year on average, but Attardo said these incidents are immensely underreported. Estimates have found the actual number may be closer to 14,100.
“When you hit an elk or deer, you're taking away one of our most precious resources in Colorado," he said. "In Colorado, our economy that's related to hunting, angling and wildlife-related tourism is around $5 billion a year. So, there's a significant economic investment in our wildlife as well.”
The latest data from CDOT shows that La Plata County, Douglas County and El Paso County have had the most recent wildlife-vehicle collisions, as of 2022.
The cost to the driver afterward is typically pricey too. On average every year, Coloradans who crash into large wildlife have to pay about $80 million in property damage, including $66.3 million annually in medical expenses, according to CDOT and the Colorado Wildlife & Transportation Alliance.
That alliance group was created in the wake of the Inaugural Colorado Wildlife and Transportation Summit in 2017. At the summit, agencies including CDOT and CPW representatives, as well as federal, tribal, academic, nonprofit and engineering partners developed a plan to share resources, secure project funding and raise awareness about wildlife-vehicle collisions and wildlife connectivity.
Members meet quarterly to go over updates on priority projects and funding and policy issues. Forty-five organizations participated in the 2023 summit.
One of the members of the alliance group is ARC Solutions, led by Executive Director Renee Callahan. She explained that wildlife crossing problems can reach resolutions in three different ways: change driver behavior, change animal behavior, or physically separate the two.
By choosing the latter and installing wildlife crossings, CDOT has reported an average decrease of 90% in the number of wildlife-vehicle collisions in the past few years in impacted areas.
"In some of the cases, we've seen a 97% reduction in crashes," Callahan said. "So, if you had 100 crashes last year on this 10-mile stretch of highway, now you have three. There's really not another transportation infrastructure investment I'm aware of that is going to get you that kind of a return on investment.”
How wildlife crossings came to be in Colorado
Initially, officials held onto the perception that preventing wildlife-vehicle collisions was simply too difficult to solve.
"How could you possibly know where to do something about this issue, because it was perceived as random, right?" Callahan said. "It was random whether you would get in an accident with an animal or not. And of course, that's where data comes in.”
Areas now called "hotspots" became apparent once they were monitored. Migrating animals crossed the same stretch of highway each year. Armed with years-worth of crash statistics, it didn't seem so random.
The Colorado Wildlife & Transportation Alliance identified eight high-risk areas for collisions with wildlife around the state, which include Interstate 70 at Floyd Hill and Eagle, US 285 in Morrison, Highway 93 between Golden and Boulder and more.
Once a location for a crossing is selected, the design process goes holistic, Attardo explained. National and state agencies, among other groups, collaborate to plan the safe passageway for the targeted species.
"Animals are like people, they like different things," he said.
Deer, bears and mountain lions seem at relative ease using an underpass. Elk, bighorn sheep and pronghorn are much more inclined to use an expansive overpass. Small critters like mice, voles, weasels, snakes and protected frogs are included too — several Colorado structures now have a row of twigs and sticks that they can hide in as they cross.
CPW Wildlife Movement Coordinator Michelle Cowardin said the animals need to see through the structure and understand that their habitat continues on the other side. Tunnels that are too long will frighten many species, though in some cases, they seem to lend a hand to one another.
Elk, which may be hesitant to try an overpass, will sometimes follow deer as they bound across.
"It's a learned behavior," Cowardin said. "So it really depends on the species. Species like moose and deer and coyotes, you know, they tend to take these pretty quickly. I would say elk, probably pronghorn, depending on the type of structure, could be a little bit more hesitant. And then bighorn sheep — they tend to like probably more of an overpass than an underpass, but we've seen them use both.”
When CDOT decides to begin planning for a new project that includes any kind of roadwork, they typically reach out to CPW staff at the regional or local level to loop them in, Cowardin said.
"And we'll start communications there. A lot of times, I'm brought in as the wildlife movement coordinator. One of my responsibilities is helping design the wildlife crossing structures," she explained.
Together, CDOT and CPW visit the site, look at wildlife movement patterns, human disturbances already in place, land ownership, geology, drainages and more, she said. The conversations about a single project can carry on for years.
“We'll stay engaged that entire time to make sure the functionality of what we've designed, and talked about designing, stays true throughout the process," she said.
Proof of concept: 'One of our gold stars'
The most recent wildlife crossing was just unveiled on June 20 at I-70 and Genesee, which had the highest number of wildlife-involved crashes on the interstate east of the Eisenhower-Johnson Memorial Tunnel, CDOT reported. In addition to the underpass, crews also installed wildlife fencing along both sides of the road from exit 254 at Genesee to exit 256 at Lookout Mountain.
This is the first wildlife crossing along the I-70 mountain corridor.
CDOT and CPW expect a variety of animals to take advantage of the safe crossing, including elk, mule deer, black bears, coyotes, mountain lions and bobcats as they move daily and between seasonal ranges.
While the Genesee underpass is the latest component of a statewide plan, it stemmed from continued success beforehand.
Completed in 2016, the Colorado Highway 9 Wildlife Crossing Project was dubbed by both Cowardin and Attardo as one of the most important crossing systems the state has constructed because of its lengthy joint wildlife overpass and underpass network.
It was the first project Cowardin worked on and she called it "one of our gold stars" because it is the state's largest system designed for wildlife.
The project encompassed two overpasses — the first two in the state — five underpasses, more than 60 wildlife escape ramps, 29 wildlife guards and nine pedestrian walk-throughs over 10 or so miles between Green Mountain Reservoir and Kremmling.
“Highway 9 is a winter range area, and so animals — deer and elk, pronghorn — come down to that area in October or November, and then they're there all the way through April and May," Cowardin said. "State Highway 9 — it was a narrow two-lane highway. It gets a lot of black ice and severe winter conditions. People go really fast because they're going from I-70 or the airport all the way to Steamboat.”
CDOT reported that about 63 animal carcasses — 98% of which were mule deer — were found on that stretch of highway each winter. Between 2007 and 2011, more than a third of all crashes there involved wildlife, CDOT said. Once the crossings were completed in 2016, researchers saw a near-immediate success.
“We went from maybe 60, 70 or more collisions that we counted — that doesn't account for all the collisions that we don't know of or carcasses that we don't know of — and we went down to eight or six or less a year," Cowardin said. "And so on State Highway 9, we saw a 90% reduction in wildlife-vehicle collisions. And then the other key part about State Highway 9 is we saw over 112,000 successful mule deer movements on those seven structures over five years (2015-2020).”
Deer began using the underpass before crews were even done with the fencing, Cowardin said. Trail cameras captured images of 16 other species, including elk, bear, moose, pronghorn, bobcats and even bighorn sheep using the crossings.
Another major wildlife crossing project in Colorado is embedded in the I-25 South Gap Project.
As drivers started to experience the project benefits of wider shoulders, express lane additions, improved truck access and new asphalt, crews built four wildlife underpasses, refurbished a fifth, and installed wildlife fencing to ensure animals could find a safe passage across the busy interstate. In addition, 65 one-way wildlife escape ramps were erected in case an animal found itself on the wrong side of the fence.
"We are looking to reduce wildlife vehicle collisions by at least 90% with this system," Attardo said. "We knew going into the construction of this project that at least 10% of the traffic delays were related to people hitting wildlife in this corridor, so we can get rid of those traffic delays as well — big thing."
A research project set up along the stretch of the project is tracking the critters using the passageways, and will be finalized in two to three years. Trail camera footage shows tens of thousands of animals using the crossings already, Attardo said.
In the other corner of the state, U.S. Highway 160 between Durango and Pagosa Springs was targeted as a place that would heavily benefit from wildlife crossings because of the huge migration corridors of elk and deer. CDOT said this project, which is being completed in stages, is expected to reduce wildlife-vehicle collisions by 85% in an area where more than 60% of all crashes involve an animal.
The U.S. Highway 160 crossings are part of a $99 million project to address safety problems on the highway, and includes better shoulders and more and wider lanes in addition to wildlife mitigation systems, Attardo said.
A recent $59 million grant from the Infrastructure Investment Jobs Act — which provided about $1.2 trillion nationwide for transportation improvements, including, for the first time in the country's history, a chunk directly allocated toward wildlife mitigation systems — will fund three additional wildlife underpasses, with construction starting this fall, Attardo said.
These safe passageways are pricey. But the data doesn't lie and the proof is evident.
"Removing the surprise of animals running out in front of you, and people swerving or hitting their brakes and causing an accident — these types of projects (are) a win-win for everybody, even though the projects do cost a lot of money," Cowardin said.
A cost-benefit analysis demonstrates a decades-long positive benefit, she added.
"These systems that cost millions of dollars — they actually can pay for themselves," Attardo said. "If we know they're 90% effective, we can reduce crashes, we can reduce the amount of wildlife that get hits and all that translates into money. And these things end up paying for themselves in 15 years, thereabouts.”
Upcoming projects: Greenland Open Space, Vail Pass and beyond
Hundreds of locations around Colorado are in need of wildlife crossings, which means the state had to whittle down the list to a few high-priority spots. As of now, five to six are in the construction phase while seven are in the design phase or waiting to be designed, Cowardin said.
About 20 crossing structures are coming onto the landscape soon, or were just completed, she said.
“Ten to 12 years ago, Colorado was a little bit behind other states like Wyoming and maybe Arizona or some of these other states, but when you start adding them up — we've really, in the last 10 or so years, put a commitment to these structures," she said.
CDOT is moving forward with many of those projects, including the Interstate 25 Greenland Wildlife Overpass Project in Douglas County. It is the final stage of the I-25 South Gap Wildlife Crossing Project and one of the top priorities for the Colorado Wildlife & Transportation Alliance.
Once completed, the overpass, located at milepost 165.4 near the Greenland interchange on I-25, will span six lanes of interstate traffic, connecting 39,000 acres of habitat on both sides of the interstate between Denver and Colorado Springs.
"Two hundred feet wide, about 400 feet long," Attardo described. "When constructed, it's going to be the largest structure in North America for wildlife use. And we need that big honkin’ structure because the target species we're looking at are big trophy elk herds that use this area that are trying to go back and forth across I-25 in this area."
Construction is set to begin later this year or early 2025, according to ARC Solutions.
With a $30 million price tag, this project is one of 19 projects the U.S. Department of Transportation (DOT) is funding through the Wildlife Crossing Pilot Program, which was created by the Bipartisan Infrastructure Law. That law made $350 million available over five years for the pilot program, and $22 million of that will go to building this wildlife overpass. The remaining $8 million for the overpass came from CDOT and the Colorado Wildlife and Transportation Alliance via state Senate Bill 22-151 "Safe Crossings for Colorado Wildlife and Motorists."
Another major plan in the works is the East Vail Pass wildlife crossing project, which would include two underpasses and one overpass in the westbound lanes of I-70 at the pass, on top of one span bridge already in place at Corral Creek.
East Vail Pass frequently popped up in studies as a place that would benefit greatly from a wildlife crossing, as about 23,000 vehicles use the stretch of road, on average, every day.
The planned underpasses and overpass would help connect wildlife to five existing large span bridges on eastbound I-70, which allows them to safely cross all lanes of the highway, according to Summit County Safe Passages.
Vail Pass is home to healthy populations of elk — which favor overpasses instead of underpasses — deer, moose and bighorn sheep. In June, one of the state's reintroduced gray wolves was spotted on a trail camera within a quarter mile of the pass. Canada lynx — a federally threatened medium-sized cat that was reintroduced in southwest Colorado in the 1990s — have moved north toward I-70, but have not established a breeding population north of the interstate, said Stefan Ekernas, director of Colorado Field Conservation for the Denver Zoo Conservation Alliance. In the past 20 years, four Canada lynx were killed on I-70.
"We've known for a long time that I-70 is a big problem, particularly for cutting landscapes in half, and especially at Vail Pass, where there's really great habitat on both sides of the highway — the Eagle's Nest Wilderness to the north of the highway and then really intact, good Forest Service landscapes to the south also," he said.
As of now, the East Vail Pass project is about 60% designed, thanks to $2 million from municipalities, state funds, ski resorts (including Vail Resorts and Arapahoe Basin), private dollars and grants from the National Fish and Wildlife Foundation.
"CDOT is submitting an application for federal money, specifically for the wildlife crossings pilot program, which is part of the Bipartisan Infrastructure Law from a couple of years ago, that’s specifically for wildlife crossings," Ekernas said. "And so you know, we're cautiously optimistic that that grant will be successful.”
That grant is due in September and awardees will likely be announced sometime this winter.
“We’re really seeing Colorado become a leader in wildlife crossings," Ekernas said.
Other wildlife crossing projects in the works include:
- US Highway 40 near Empire for bighorn sheep has also been targeted for an overpass, as the state's largest and most healthy herd calls that area home. That crossing has already been designed. (Part of I-70 Floyd Hill Project)
- Wildlife mitigation systems at the Colorado-New Mexico border
- Wildlife mitigation systems on US Highway 40 near Craig
- Wildlife mitigation systems on US Highway 87 north of Fort Collins
Boulder County just recently started investigating the feasibility of building a wildlife crossing on Highway 36 between Boulder and Lyons, specifically between Lefthand Canyon Drive and State Highway 66.
Callahan said Colorado has an "incredible window of opportunity" as infrastructure around the state built nearly 100 years ago begins to reach the end of its lifespan.
"And for better or worse over the next decade-plus, across the nation and including in Colorado, we're going to be investing in these facilities and we're going to be bringing them up to the new standard," she said. "To me, that new standard absolutely has to include wildlife considerations."
