The Washington State Department of Transportation broke ground Tuesday on a wildlife overpass crossing I-90 east of Snoqualmie Pass.
The $6.2 million structure is part of nearly a billion dollars of upgrades planned to a 15-mile stretch of I-90 between Hyak and Easton.
The overcrossing is designed for wildlife, especially elk and deer, to safely cross the highway and avoid colliding with cars.
It will be WSDOT's first wildlife overpass.
King County previously opened a wildlife crossing over Novelty Hill Road.
Charlie Raines of the I-90 Wildlife Bridges Coalition says crossings are proven to work, and he thinks the I-90 design will improve on those used elsewhere.
"You don't pass out maps to wildlife, they have to find it. But they will find it," Raines said.
Fences will be placed near the crossings to keep animals off the roadway and send them toward the crossing.
WSDOT already has two wildlife underpasses in earlier phases of the project.
The groundbreaking on Tuesday also marked the start of construction of 2 more miles of the highway widening project, bringing the stretch of I-90 east of Snoqualmie Pass from four lanes to six.
State officials said the first 5 miles, costing $551 million, came in about a hundred million under budget, allowing the state to break ground on 2 more miles.
The final 8 miles to Easton remain unfunded and will cost about $400 million, said WSDOT Regional Administrator Don Whitehouse.
Upgrades include straightening the roadway, building more chain up areas, and creating avalanche bridges to reduce the need for avalanche control closures in winter.