All about Wildlife Overpasses and Underpasses

The conversation on the floor of a recent off-Reecer-Creek meeting of the Reecer Creek Rod, Gun, Working Dog & Outdoor Think Tank Benevolent Association was the upcoming video and discussion of our Snoqualmie Pass I-90 wildlife crossings. This is co-sponsored by the 99+ year-old Kittitas County Field and Stream Club and the Ellensburg Public Library, and happens Monday evening, September 10 at Hal Holmes. The presentation will be made by folks from the I-90 Wildlife Bridges Coalition of Washington.

At any rate, Homey just looked at me. Finally, he shook his head and asked the most common question I hear about these crossings, “Do critters actually use those overpasses and those places where they go under highways?”

“Yes. And yes,” I replied. “There are hundreds of wildlife crossings around the world, and they are credited with saving thousands of two-legged and four-legged lives. One or two of them have been developed for animals you probably never even considered…”

Probably the most widely-known and photographed crossings in North America are those around Canada’s Banff National Park in Alberta. Our Snoqualmie Pass crossings are the largest wildlife crossings project in North America. They will, I think, be as celebrated and discussed – and as popular to tourists – as those around Banff.

Wildlife crossings – overpasses and underpasses – have been built all across the world. In the U.S. you will find them in Montana, Colorado, California, Florida. New Jersey, Nevada, and several other states. In Sublette County, Wyoming built the first overpass designed specifically for pronghorns – to protect a couple thousand antelope which migrate 160 miles each way – with special vegetation and a very unique design. Across the globe, wildlife crossings are found in (among many others) The Netherlands, Germany, Belgium, South India and Australia. Google “wildlife overpasses” and you will find photos and videos of worldwide animal bridges, and links to an amazing variety of studies which support the value of these crossings.

While we think mostly about preventing human-animal collisions, a primary motivation for finding crossing solutions has been the fragmenting of wildlife habitat – the division of contiguous wildlife ground – by ever-increasing numbers and sizes of highways, and the traffic they carry. Crossings allow animals of all sizes and species to move more freely – and safely – through historc range.

Of course, the cost of vehicle-animal collisions is significant both in terms of property damage and deaths/injuries to human drivers and passengers. Wikipedia (under that “wildlife overpasses” Google) cites dozens of studies, with some mind-boggling numbers. In 1996, Bruinderink & Hazebroek estimated annual European human/ungulate collisions at more than half a million, with 300 human deaths and 30,000 injuries. In the U.S., Donaldson’s 2005 study cited one and a half million traffic accidents involving deer, annually, causing more than one billion dollars in vehicle damage. Other studies cite up to 30,000 injuries, with more than 200 fatalities, each year in the U.S.

Wildlife crossings are not cheap, but arguments are made that planning and construction costs are trumped (word used in its traditional meaning) by wildlife population and habitat protection, reduced vehicle and property damage, and lives saved by fewer collisions. (A Virginia Department of Transportation study estimated that underpasses for wildlife become cost effective if they prevent between three and nine car-deer collisions annually – depending on the cost of building the crossing.)

Add all those costs to concerns about wildlife mortality and habitat fragmentation, and it is easy to see why biologists, engineers, and transportation pros have been looking at mitigation tools to reduce conflicts between roads and wildlife. It appears that, while proper siting and proper design for species, habitat and so forth is critical, wildlife crossings have been most successful at meeting those concerns.

On September 10, you will have a chance to see where our I-90 corridor fits in this worldwide work. Cascade Crossroads is a 30-minute documentary film chronicling the work over and under Interstate 90 just east of Snoqualmie Pass over the Cascade Mountains. These crossings grew from the work of the I-90 Wildlife Bridges Coalition, formed in 2004 by more than two dozen organizations and businesses. The Coalition’s mission was “to advocate for high quality wildlife connectivity measures in the I-90 Snoqualmie Pass East Project, while ensuring the habitat adjacent to these structures contributes to their success.”

Find out more about the I-90 project at And find more about the film at

Washington State is now fully in the wildlife crossing game. Our overpass and underpass crossings will be as successful as they are striking. Join the I-90 Wildlife Bridges folks for a beautiful video and fascinating discussion. Hal Holmes, Monday, 10 September, 7 p.m. Come learn the things you will use to impress friends when they visit Paradise.

Written by Jim Huckabay. Posted in Uncategorized

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Comments (2)

  • Patty
    September 5, 2018 at 12:07 am |

    Hi Jim! The column is great! However, the hardcopy of the paper cut off some of the story (the part about the date of the presentation). Also, the presentation is not by the I-90 Wildlife Bridges Coalition. It will be U.S. Forest Service (Patty Garvey-Darda, Wildlife Biologist and Liaison to WSDOT for the I-90 Snoqualmie Pass East project), Washington Department of Transportation (Brian White, Professional Engineer and Assist Regional Administrator– WSDOT South Central Region), Ted Grudowski (Cascades Crossroads videographer that produced the film). The film will take 30 minutes and then Brian and I will present information on the entire project and future construction. Between the 3 of us we will be able answer questions related to wildlife, engineering, and film making. Again, thanks for the great column! I hope folks show up–its considered one of the biggest and best wildlife connectivity project’s in the world. . .and its in our backyard!

    • Jim Huckabay
      September 10, 2018 at 8:52 pm |

      Yeah… This is why Matt my editor added the remainder of info from the column to Wednesday’s paper (with pictures).. This was a first for me and a bit irritating, but…

      (It WAS whole on the web…) JLH

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