1D: Evaluating Crossings at Parleys Canyon Overpass

Roadways threaten migratory ungulates by creating a barrier to movements and preventing access to seasonal migration routes. To mitigate these conflicts, state transportation agencies often install wildlife crossing structures to allow animals to safely cross over or under roadways. In 2018, the Utah Department of Transportation installed a uniquely narrow overpass in Parleys Canyon, across Interstate 80. Researchers at USU studied if mule deer and moose would use the structure. Using trail cameras installed along Parley’s Canyon Overpass from May 2020- September 2024, they recorded wildlife use of the overpass. Over 4,300 unique visits to the overpass were counted, involving at least 34 species. The most common animal detected in the vicinity of the overpass were mule deer, with more than 3,600 visits to the site, and about one crossing per day. By comparison, they detected moose in the area near the overpass about 150 times, an average of 5 crossings per 100 nights, and coyotes were detected 500 times, with seven crossings per 100 nights. Most of the time (98%) when a deer or moose attempted to cross the overpass, they successfully completed this crossing. Elk were rarely detected in the vicinity of the overpass, with only three successful crossings during the study. Parleys Canyon Overpass, while unconventional in size, was quickly and successfully used by wildlife, resolving a barrier to crossing Interstate 80. This facilitation of movement for deer and moose will contribute to the overall health of these populations while decreasing dangerous wildlifevehicle collisions, with an estimated $15 million taxpayer savings in motor vehicle collisions over its lifetime.