A wildlife overpass in Washington reached a major milestone: 10,000 documented safe crossings over Interstate 90 at Snoqualmie Pass.
The achievement is a triumph of lower public costs and a safer route for travelers passing through the corridor.
Here's what to know
Nearly 40,000 crossings have been recorded on Snoqualmie Pass since 2014 at the wildlife overcrossing and 11 undercrossings, as Good Good Good reported. Of that total, trail cameras have documented 10,000 successful animal trips across the I-90 wildlife overcrossing alone, according to the Washington State Department of Transportation.
"Want a success story? In July, we recorded the 10,000th successful crossing on our I-90 Snoqualmie Pass wildlife overcrossing," the agency wrote on Instagram.
Built to allow animals to avoid traffic, crossings prevent collisions that can injure or kill drivers and wildlife. Per Good Good Good, The Pew Charitable Trusts said the infrastructure can cut deer and elk collisions by up to 97%, and overpasses, underpasses, and fencing cut crashes by over 90%. They also prevent vehicle, injury, and wildlife costs — which reach $110,000 per moose.
"Between 2019-2023, we removed 39,258 carcasses from state highways," WSDOT stated. "In the stretch of I-90 Snoqualmie Pass where the overcrossing and undercrossings exist…that number has shrunk to nearly zero."
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More background
Snoqualmie Pass sits within a major habitat corridor that connects wildlife populations in the Cascades. Roads fragment that habitat, making it hard for animals to find food and mates or move seasonally.
WSDOT said the benefits extend beyond avoiding collisions.
"There's a few reasons we built these structures. For one, it allows wildlife to safely access their full range of habitat. Isolated wildlife populations lead to weaker genetics over time," the agency explained.
WSDOT noted the average cost of a deer collision is about $15,000 and an elk collision can reach $54,000. Reducing those crashes also means fewer injuries, vehicle repairs, and emergency response burdens as well as safer travel for everyone using the interstate.
"Since 2019, this structure has helped restore the ecological integrity of the North and South Cascades by reducing wildlife vehicle collisions, reconnecting habitat, and allowing herds and solitary travelers alike to move safely through one of Washington's most important wildlife corridors," Conservation Northwest said.
What's being done?
Conservation Northwest pointed out the success at Snoqualmie Pass has strengthened the case for combining transportation planning with habitat protection.
WSDOT said that it has plans to build 15 undercrossings and one overcrossing along Snoqualmie Pass East between now and 2031.
"Our mission is keeping travelers connected to wherever they need to go, no matter if it's by wheel, foot, paw, or hoof," it added.
Where can I learn more?
Snoqualmie Pass is one example of efforts to reconnect habitat and cut down on deadly highway crashes. Similar projects in Alberta, Western Australia, Massachusetts, Los Angeles, and Northern California show how these structures are changing roads for animals and drivers alike.
• In Banff National Park, wildlife crossings prevent collisions while thousands of animals move safely each year.
• Along Western Australia's highway, 75 animals a night now use crossings once dismissed as unnecessary.
• In Massachusetts, officials will build a massive bridge over I-90 to reconnect fragmented wildlife habitat.
• Near Los Angeles, crews reached a major milestone in construction of the world's largest wildlife crossing.
• In Northern California, three mule deer crossed an unfinished overpass and made state history.
These projects show that wildlife-friendly infrastructure can improve human safety as well. That's a big reason Washington's crossings are drawing attention as a model for future work.
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