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West-Wide Assessment of Cost-Effective Opportunities for Mitigating Wildlife Vehicle Collisions

Project #: 4W9201
Start Date: 07/30/2021
End Date: 09/30/2022
Status: Completed

Wildlife-vehicle collisions (WVCs) on roadways with large animals significantly impact property, human health and safety, and wildlife populations. WVCs now represent 4-5% of all collisions in the United States and are responsible for approximately 200 deaths and 26,000 injuries every year. All told, the annual economic cost of WVCs from death, injury, and property damage is estimated to be 8.4 billion dollars. Beyond the social and economic costs, WVCs also impose a brutal toll on wildlife populations; millions of large animals die on the nation’s roadways each year, and roads and traffic impact populations indirectly by creating barriers for species movement and migration.

In recent years, policymakers have started paying attention to these issues and Congress earmarked hundreds of millions of dollars in proposed transportation legislation for states to build wildlife crossing structures and related mitigation measures. In 2016, the U.S. Department of the Interior’s Secretarial Order 3362 directed agencies to work with western States to identify migration corridors; roads were subsequently identified as the primary movement barriers for mule deer, elk, and pronghorn. Western states, such as Arizona, Washington, Colorado, Oregon, and New Mexico, have all passed legislation or issued executive orders that direct wildlife and transportation agencies to assess and mitigate WVCs. Indeed, research shows that wildlife mitigation strategies, such as fencing and wildlife crossing structures, are highly effective at reducing WVCs and improving wildlife migration, however, mitigation measures are often considered by transportation agencies to be prohibitively costly. Understanding where WVCs occur most frequently and where mitigation will be cost-effective is therefore essential for effective transportation planning and efficient allocation of scarce public and private resources.

Project results have the potential to significantly influence transportation policy and planning and increase the pace and scale of WVC mitigation. At the federal level, scalable and spatially explicit data on WVCs and cost-effective mitigation can be used to inform strategic planning, partnership development, and efficient NEPA implementation for large-scale federal transportation projects (a Biden administration priority). At the state level, project maps and reports can help transportation and wildlife agencies identify priority areas and road segments for mitigation, a process many western states are currently wrestling with. Indeed, conversations with state agencies and NGOs working on this issue have underscored the importance of the project for informing transportation decision-making, particularly if and when transportation funding for WVC mitigation and wildlife crossings is approved and allocated by Congress.


The objective of this project is to support the design and implementation of federal and state policies to reduce wildlife-vehicle collisions (WVCs) and improve wildlife movement. The Center for Large Landscape Conservation (CLLC) and the Western Transportation Institute (WTI) propose to use their extensive experience to develop a West-wide assessment of WVCs that pinpoints opportunities for cost-effective mitigation. Project deliverables will include (1) a spatial dataset of WVC hotspots, and (2) a cost-benefit analysis that identifies highway segments where the economic benefits of providing mitigation for wildlife surpass the costs. The report will summarize where WVC mitigation opportunities are economically beneficial West-wide, by state and by county. Based on the analyses and report, CLLC and WTI will conduct webinars and other presentations as well as create fact sheets and briefings for policy makers and managers at state and federal levels of government.