research hair on fence

Mixed-use landscapes such as agricultural areas, towns, and villages are where most wildlife-vehicle collisions occur. But to date, most of our knowledge about the effects of traffic on wildlife comes from research conducted in protected areas like national parks, national forests, and preserves—where human impacts are at a minimum.

With the US 93 North reconstruction project, that changed.

The mitigation measures put into place on US 93 North provide an unprecedented opportunity to evaluate the effectiveness of wildlife fences and wildlife crossing structures in an area used by both by wildlife and humans. The reports listed below summarize the effectiveness of the mitigation measures and distinguish between human safety, wildlife habitat connectivity, and cost-benefit analyses. The outcomes of the research were used to formulate recommendations for best management practices for wildlife-vehicle collision reduction and wildlife crossing mitigation projects throughout North America and beyond.

Data collection and monitoring methods included:

  • Collection of the number of animal-vehicle collisions through Montana Highway Patrol crash reports, Montana Department of Transportation (MDT) carcass removal reports, and bear road mortality data from natural resource management agencies.
  • Digital motion-sensitive wildlife cameras at the majority of crossing structures, wildlife guards (similar to cattle guards), ends of fences, and jump-outs
  • Sand tracking beds at jump-outs and selected crossing structures
  • Deer pellet group surveys to measure potential changes in the deer population size 


After 14 years of data collection and monitoring, the final report details the challenges and successes of the wildlife mitigation structures:



Other Research on US93N

Research on 93Nwildlife crossing structures has been completed by several graduate students:

Allen, Tiffany Dore Holland, "The Use of Wildlife Underpasses and the Barrier Effect of Wildlife Guards for Deer and Black Bear", 2011 (PDF)

Allen, T.D.H, M.P. Huijser & D. Willey. 2013. Evaluation of wildlife guards at access roads. Effectiveness of wildlife guards at access roads. Wildlife Society Bulletin 37(2): 402–408. (Article)

Andis, A.Z. "Performance Measures of Road Crossing Structures From Relative Movement Rates of Large Mammals", 2016 (PDF)

A.Z. Andis, M.P. Huijser and L. Broberg. Accepted. Performance of Arch-style Road Crossing Structures from Relative Movement Rates of Large Mammals. Frontiers in Ecology and Evolution. (Article link coming soon)

Connolly-Newman, Hayley R., "Effect of Cover on Small Mammal Abundance and Movement Through Wildlife Underpasses" (2013). (PDF)

Fairbank, Elizabeth Rose, "Use and Effectiveness of Wildlife Crossing Structures with Short Sections of Wildlife Fencing", 2014 (PDF)

Purdum, Jeremiah P., "Acceptance of Wildlife Crossing Structures on US Highway 93 Missoula,Montana", 2013 (PDF)


Student Art Contest


The People's Way Partnership conducted the Safe Passages for Wildlife poster contest to teach school-age children about the importance of wildlife crossing structures under and over highways for both human and wildlife safety.
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Please download this page (PDF) to send funds towards the People's Way Partnership outreach efforts!


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