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US 93 Post-Construction Wildlife-Vehicle Collision and Wildlife Crossing Monitoring Research

Project #: 4W2972
Start Date: 01/15/2010
End Date: 07/31/2016
Status: Completed

The final report summarizes research conducted between 2002 and 2015. The research focused on the effectiveness of the mitigation measures in reducing collisions with large mammals, and the use of the crossing structures (specifically by white-tailed deer, mule deer, and black bear). In addition, the effectiveness of wildlife guards (similar to cattle guards), wildlife jump-outs and a human access point was evaluated. Finally, the researchers conducted cost-benefit analyses and formulated recommendations.


The US Highway 93 (US 93) reconstruction project on the Flathead Indian Reservation in northwest Montana represents one of the most extensive wildlife-sensitive highway design efforts in North America. The reconstruction of the 56 mile (90 km) long road section includes the installation of 41 fish- and wildlife crossing structures and approximately 8.3 miles (13.4 km) of road length with wildlife exclusion fencing on both sides of the road. The mitigation measures are aimed at improving safety for the traveling public through reducing wildlife-vehicle collisions and allowing wildlife to continue to move across the landscape and the road. In 2002, prior to US 93’s reconstruction, WTI (in partnership with FHWA and the Montana Department of Transportation) initiated a before-after field study to assess the effectiveness of the wildlife mitigation measures. Preconstruction field data collection efforts were completed in the fall of 2005 and a final report on the preconstruction monitoring findings was published in January 2007. This follow-up project will incorporate post-construction monitoring to collect data for before-after comparisons. The focus of the evaluation will be to investigate whether mitigation efforts enhance human safety (through reduced wildlife vehicle collisions), maintain habitat connectivity for wildlife, and are cost-effective. This effort is conducted by WTI, in partnership with Confederated Salish & Kootenai Tribes (CSKT), the Montana Department of Transportation, and the Research and Innovative Technologies Administration of USDOT. This project represents the portion sponsored by MDT.


WTI will implement a five year post-construction monitoring plan in conjunction with the Salish Kootenai Confederated Tribes to measure the effects of over 40 wildlife crossings and fencing on the following two parameters: 1) wildlife-vehicle collisions and 2) wildlife movements across US Highway 93.

The objective of this project is to conduct post-construction monitoring of the wildlife mitigation efforts on US 93, and conduct an analysis of their effectiveness. The research centers on the benefits for human safety, habitat connectivity for wildlife, and a cost-benefit analysis.