EAGLE COUNTY, Colo. — The final season of construction for a stretch of Interstate 70 in Colorado — which includes wildlife crossings, avalanche mitigation and rockfall prevention — will begin Monday.
The Colorado Department of Transportation (CDOT) announced the I-70 West Vail Pass Auxiliary Lane Project, which began in 2021, is nearing completion and is expected to be wrapped up by the end of 2026. The project aims to improve road safety along a span of 10 miles between the East Vail Interchange and Vail Pass Rest Area.
In this final phase, CDOT said its crews will focus on the remaining road and paving operations, wildlife crossings, installing mitigation infrastructure for avalanches and rockfall, and final touches on the recreation path beneath the new bridges.
As of Tuesday, several parts of this project are already complete, including:
- Two new bridges near mile point 185
- A 2.7-mile eastbound auxiliary lane between mile point 187.3 and 190, which serves as a climbing lane for slower vehicles
- Reconstruction of about 2 miles of the Vail Pass recreation path
- Enhanced drainage systems to protect Gore Creek
- Installation of 5 miles of critical fiber-optic conduit
- Expansion of the parking lot on Big Horn Road
- Roadway resurfacing between mile point 179 and 185
The story below dives into what the remainder of this project will look like in 2026.
Vail Pass wildlife crossings
By the end of 2026, wildlife around Vail Pass will have new and safe ways to get around I-70 without stepping foot — or paw or hoof — on the roadway.
Denver7 published our in-depth report on wildlife crossings in September 2024, when we spoke with experts about collisions, data and the importance of upcoming projects across Colorado. Watch that below.
Two of those crossings are geared toward larger animals and four are more suited for small and medium-sized animals. All of the crossings will go under I-70 between mile point 187 and 190.
Crews will also build wildlife fencing starting five miles west of Vail Pass up to Vail Pass, which will help guide the animals to the safe crossings and prevent them from trying to cross the interstate.
Denver7 stories on Colorado's wildlife crossings
New habitat study reveals biggest challenges for Colorado's Canada lynx Project to build new wildlife crossing in southwest Colorado is now complete How Colorado quickly became a nationwide leader in wildlife crossings Largest wildlife overpass in North America opens in Douglas CountyThe Vail Pass Recreation Path, which runs alongside the interstate and overlaps with some of the wildlife crossings, will stay open during this construction.
Officials may need to pause people on the trail, but no extended closures are scheduled, CDOT said.
Vail Pass mitigation systems for avalanches and rockfall
CDOT said new avalanche and rockfall mitigation infrastructure will be completed at mile point 186 on I-70, also nicknamed "The Narrows."
"This system — the first of its kind in Colorado — will enable CDOT and the Colorado Avalanche Information Center (CAIC) to safely monitor and manage a known avalanche path, reducing the likelihood of extended interstate closures," the department said.
Denver7 reported on this work in July 2025, when CDOT crews delivered materials for a first-of-its-kind avalanche and rockslide fence to a hilltop near mile point 186. The infrastructure can mitigate both types of slides.
John Kronholm, resident engineer for CDOT, told us that that type of fencing has not been used anywhere else.
Denver7 was at Vail Pass to witness the delivery of materials for the fencing last summer. Watch our report below.
He said sometimes an avalanche slide will cross all four lanes of the interstate, which requires about five or six hours of work to clear it off the road.
“The idea behind the fence is that it's going to eliminate the need for active avalanche mitigation by triggering the slide. So, this is all passive avalanche mitigation,” Kronholm said.
The final work for this system will require traffic holds for about 20 minutes.
So, what's the impact on drivers?
CDOT explained that beginning on April 20, single-lane closures are possible each day in both directions of I-70 between the East Vail Interchange and Vail Pass Rest Area.
In May, all I-70 traffic will shift to the south "into a head-to-head, barrier-separated alignment in the new eastbound lanes" so crews can construct a wildlife underpass, CDOT said.
Then, in early or mid-June, crews will start rock-scaling work, which will require temporary traffic holds Mondays through Thursdays between 9:30 a.m. and 2:30 p.m. CDOT said "only a few" traffic holds are expected during this time and they should last about 20 minutes, though delays are possible.
Night work is likely as the weather warms up and will become more consistent this summer.
To learn more about I-70 driving conditions and updates, visit CDOT's new resource page for the interstate's mountain corridor here. To stay updated on the latest with this portion of I-70, text "vailpass" to 21000.
"As we enter the final season of this critical project, our focus is on a safe and successful project completion," said CDOT Executive Director Shoshana Lew. “From new bridges and pavement to wildlife crossings and avalanche and rockfall mitigation, every element of this work will make Vail Pass more resilient, reduce crashes and closures, and provide a more reliable and enjoyable trip for everyone traveling the I-70 Mountain Corridor."
