An exploration of the high cost of wildlife-vehicle collisions and the
many challenges to transforming the U.S. road network.
Documentation of the safety, ecological, economic, and social benefits
anticipated to accrue from investing in highway crossings for wildlife,
including enhanced motorist safety, reduced wildlife mortality, and improved
Identification of policy and funding improvements and activities that
would further support the deployment of crossing structures.
Recommendations on how to build upon successful efforts to reduce
wildlife-vehicle collisions already underway at the federal, state, local, and
WTI Road Ecology Program Rob Ament served as one of the editors for the report, and WTI Research Scientists Tony Clevenger, Marcel Huijser, and Angela Kociolek are contributing authors.
CITATION: Ament, R.; Jacobson, S;
Callahan, R.; Brocki, M., eds. 2021. Highway crossing structures for wildlife:
opportunities for improving driver and animal safety. Gen. Tech. Rep.
PSW-GTR-271. Albany, CA: U.S. Department of Agriculture, Forest Service,
Pacific Southwest Research Station. 51 p.
In 2018, the Utah Department of Transportation completed the state’s largest wildlife crossing, which traverses six lanes of traffic on Interstate 80. The crossing structure made the news again last week, when research footage captured deer, moose, elk, bears, bobcats and a variety of smaller mammals using the bridge. In news coverage by Smithsonian Magazine, “Animals are Using Utah’s Largest Wildlife Overpass Earlier Than Expected,” WTI Road Ecologist Rob Ament is quoted regarding the high percentage of collision reductions that typically occur after the installation of crossing structures. Rob’s quote is also included in a similar article by Nature World News.
The U.S. Forest Service
has released a new report authored by wildlife crossing experts from WTI, ARC
Solutions, and other partner research organizations, which compiles key
guidance information that may lead to the installation of more wildlife
structures are one of the most effective means of reducing animal-vehicle
collisions on highways, while facilitating essential animal movement across the
landscape. Yet the widespread implementation of such structures, especially
wildlife overpasses, has been hindered by cost concerns. In 2014, WTI hosted a
workshop in partnership with ARC Solutions and prominent wildlife crossing
experts from Canada and the United States to determine whether there are design
parameters and construction techniques that could be added, changed, or
adjusted to reduce costs, while maintaining or improving the effectiveness of
during the workshop were developed into specific strategies. This document presents 32 potential cost
savings considerations, which were consolidated into three categories:
design and construction
procurement, delivery method, and cost accounting considerations
Citation: McGuire, Terry M.; Clevenger, Anthony P.; Ament, Robert; Callahan, Renee; Jacobson, Sandra, eds. 2020. Innovative strategies to reduce the costs of effective wildlife overpasses. Gen. Tech. Rep. PSW-GTR-267. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.
The International Union for the Conservation of Nature (IUCN) has released Guidelines for Conserving Connectivity through Ecological Networks and Corridors, an international resource with best practices for maintaining, enhancing, and restoring ecological connectivity among and between protected areas. These Guidelines also include 25 case studies that demonstrate current approaches to conserving ecological connectivity and ecological networks for different ecosystems and species. One of the authors is WTI Road Ecology Program Manager Rob Ament, who has worked in partnership with IUCN for several years on wildlife connectivity issues as part of the organization’s Transport Working Group.
CITATION: Hilty, J., Worboys, G., Keeley, A., Woodley, S., Lausche, B., Locke, H., Carr, M., Pulsford, I., Pittrock, J., White, J., Theobald, D., Levine, J., Reuling, M., Watson, J., Ament, R., Groves, C., and Tabor, G. (2020). Guidelines for Conserving Connectivity through Ecological Networks and Corridors. Gland, Switzerland; International Union for the Conservation of Nature (IUCN). DOI: https://doi.org/10.2305/IUCN.CH.2020.PAG.30.en
One of the country’s leading newspapers consulted a WTI researcher and several of our road ecology publications for a national feature story on wildlife crossings. “Retrofitting busy highways to let wildlife travel safely, too” explored national and state initiatives to identify wildlife corridors and enhance crossing structures such as underpasses and overpasses. The Post interviewed Road Ecology Program Manager Rob Ament, who discussed the potential long-term genetic consequences of highways that restrict wildlife movement and connectivity. The article also cites WTI/Montana Department of Transportation research on wildlife crossings on US 93 in Montana, and a cost-benefit analysis study that documented the direct and indirect costs of collisions with large animals.
WTI is conducting a research on behalf of the Wyoming Game and Fish Department (WGFD) and the Wyoming Department of Transportation (WYDOT) to explore mitigation options for reducing wildlife vehicle collisions along Interstate 25 in central Wyoming. WYDOT and WGFD would like to explore the possibility of funneling large mammals, particularly mule deer and pronghorn, through the existing underpasses on this section of road rather than building new ones specifically designed for wildlife.
As one of the research steps, project researchers Marcel Huijser, Amanda Warren, and Elizabeth Fairbank collected preliminary data on wildlife use of existing structures under I-25 which were not originally designed for wildlife. Based on an eight-month monitoring effort in 2018-2019, the research team found that the structures are predominantly used by mule deer and white-tailed deer, but almost never by pronghorn. More details are available in the interim report (“Preliminary Data on Wildlife Use of Existing Structures along I-25, Kaycee, Wyoming, USA”), which was recently published and is available on the project page of the WTI website.
The Montana Department of Transportation (MDT) has a new webpage dedicated to facilitating collaboration among the many partners working to reduce animal vehicle collisions and enhance wildlife connectivity.
In December 2018, the Montana Wildlife & Transportation Summit (Summit) was held at Carroll College in Helena, Montana. It was co-convened by the Montana Governor’s office, Montana Department of Transportation (MDT), Montana Fish, Wildlife and Parks (FWP), Western Transportation Institute (WTI), and Montanans for Safe Wildlife Passage (MSWP). The purpose of the Summit was to bring stakeholders together to strengthen working relationships and share information. The long-term goal is to develop strategies to plan and implement wildlife accommodations, reduce animal-vehicle collisions, and protect wildlife and their movement across state highways. The emphasis of this first meeting was to build common ground among stakeholders around wildlife and transportation issues in order to build a foundation to engage additional stakeholders and partner on collaborative initiatives.