People, 8,000 elk and 2,000 mule deer now travel safer along western Idaho’s Ponderosa Pine Scenic Byway near Boise due to a new $7.5 million wildlife overpass, ending a legacy of frequent traffic crashes with big game.
This first wildlife overpass project by the Idaho Transportation Department saw 10 state and federal agencies overcome red tape, turf boundaries and budget issues to showcase how government can protect drivers and ensure wildlife resiliency.
State Highway 21 Wildlife Overpass at Cervidae PeakIdaho Transportation Department
The ITD project was funded through the Federal Highways Administration’s Federal Lands Access Program. ITD involved numerous stakeholders including Idaho Fish and Game, the U.S. Forest Service, U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the Bureau of Land Management, the U.S. Department of Agriculture’s Natural Resource Conservation Service, the City of Boise and the counties of Ada and Boise.
Also many private and non-governmental organizations gave money, resources and in-kind contributions to support required local funding matches.
“This project would not have happened or had success without their contributions and willingness to partner,” said Scott Rudel, ITD project manager for its first wildlife overpass.
The creation of the overpass was recognized Oct. 31 by the American Association of State Highway and Transportation Officials who honored ITD with a President’s Award for Environment and Planning.
Over the past 40 years, the mountainous area from Mileposts 17.2 to 19.6 had been the site of numerous vehicle accidents with large animals. SH-21 is a key north-south connector that also links east to west through central Idaho. That area has over 1 million vehicles passing over it annually.
This problem caused Idaho Fish and Game to issue a public service video about the wildlife overpass and the reasons why it is important. It stated that during 2022, over 1,500 vehicles crashed into wildlife in Idaho that resulted in $40 million in damages as well as injuries and deaths.
Residents and tourists driving along SH-21 mostly travel there to take advantage of federal lands for outdoor recreation. They may not realize how important that area is to wildlife. For instance, Boise River elk have no choice but to pass around traffic as they migrate from 63 to 26 miles each way to reach their summer and winter ranges. Mule deer wintering in the area live in foothills and have longer seasonal distances to walk (45 to 96 miles in each direction). For just over a month, they migrate every October-November for winter and April-May in spring.
ITD and the Idaho Department of Fish and Game had been tracking WVCs metrics using dead carcasses. The highway corridor saw people in vehicles colliding with wildlife at a rate of 50 per year, with that number rising to over 100 crashes during severe winters when mule deer and elk were forced to winter in less harsh lower elevations. Also wildlife can be hit by vehicles because some animals are attracted to chloride salts put on roads during winter, Rudel said.
No wildlife-vehicle collisions were reported at Cervidae Peak in a one-year period ending Oct. 31 on Utah State Route 21 highway section where ITD installed new fencing and the overpass, said Rudel. ITD’s project’s goal had been to lower the area crash rate by at least 80%.Mule deer dart over Idaho’s new wildlife overpass near BoiseIdaho Transportation Department
“Video and photographic use of the wildlife overpass by mule deer and elk tell the story of the reduction of WVCs [wildlife-vehicle collisions], enhanced mobility for both motorists and wildlife, while still maintaining that critical habitat and landscape connectivity that Idaho’s wildlife populations need to survive winters in the Northern Rockies,” Rudel explained.Night photo of wildlife using Idaho’s new wildlife overpassIdaho Transportation Department
To address the need for humans and wildlife to share spaces safely, he said multiple players must join, take ownership and have a vested interest in providing resources, input, money and in-kind contributions to projects like wildlife overpass projects.
“Mule deer, elk and other big game animals don’t know where one property boundary ends and where another begins. They do not know what is public versus private land. They do not know whose transportation right-of-way belongs to whom or where a city’s limits begin, and quite frankly they don’t care. They certainly do not understand about the hazardous safety and mobility issues that may arise when a motorist intercepts a mule deer or elk at 55 to 65 mph,” Rudel said.A mule deer walks past new fencing to cross a safe overpass as vehicles travel below on the highway … [+] in Idaho.Idaho Transportation Department
“This project lies within the Boise River Wildlife Management Area and is the primary winter range for 6,000 to 8,000 mule deer and 1,800-2,000 elk, which winter there each winter and traverse across SH-21 to do so,” Rudel said. “There is no other wintering range these animals can really utilize with all the development that has occurred in the Treasure Valley.”Overhead view of mule deer in Idaho using the new wildlife overpasse instead of dashing into traffic … [+] below in a situation that had existed for over 40 years.Idaho Transportation Department
The department now is seeking to extend the fencing to better guide the wildlife to the overpass crossing area, which will strengthen safety measures.
“Nobody wants to be involved in a WVC accident or incident that may cause trauma, may cause property damage, may cause impacts to their and their families and friends health and welfare, or may even cause death. At the same time, nobody wants to see large dead animals on the side of a highway or on the highway, experience the trauma of an animal suffering, or see the repercussions of losing our valuable wildlife and natural resources that do provide recreational, sustenance, social-economic and other cultural opportunities such as reconnecting with nature and spiritual reverence,” Rudel noted.The roadway where vehicles pass below Idaho’s new wildlife overpass. This place used to be a deadly … [+] site for mule deer, elk and people due to vehicle collisions with wildlife trying to cross the road.Idaho Transportation Department
After his experiences leading the wildlife overpass, Rudel said he wonders who should really shoulder the funding for these important projects.
“Should local land-use agencies foot the bill since they drive growth and development decisions? Should federal lands management agencies foot the bill since the habitat many of these animals live on is primarily federal lands for a good portion of the year? Should wildlife management and resource agencies foot the bill since they are responsible for managing populations and their size, numbers and other dynamics? Should DOTs and transportation agencies foot the bill because they manage our highways/roads and base projects on safety and accident criteria including property damage, injury statistics, and deaths as well as other transportation assets?” he pondered. “How do states or our federal government, Congress and the forthcoming Executive Administration feel about these issues and is it important issue for them?”
Despite the numerous hurdles and bureaucracy, ITD’s wildlife overpass project demonstrates what can be accomplished to improve the quality of lives for people and wildlife using technology, measuring effectiveness and investing in a better future for all.An unexpected fox travels at night over Idaho’s new wildlife overpass to improve traffic safety and … [+] wildlife resilienceIdaho Transportation Deparment
At the same time, this project highlights a complicated pathway that state transportation departments can explore and invest in to make travel safer, save lives and mitigate negative consequences that traffic can bring to wildlife.
