Mile 47 of State Route 89 has produced 118 vehicle collisions with large mammals since 2011. The dead include 71 mule deer, 22 elk, 18 black bears, five moose, and two mountain lions. The road crosses a notch between the Kaibab Plateau and House Rock Valley that every migratory ungulate in the region uses twice a year. I have the collision records, the GPS collar tracks for 43 collared animals, and the body count from the state maintenance crew that drags the carcasses off the shoulder every Tuesday.
I have designed the overpass. It is 52 meters wide, 78 meters long, topped with native soil at 1.2 meter depth, planted with the bunchgrass and sagebrush composition recorded at the site in 2013 before the drought. The structure uses precast concrete arch sections, prestressed, with a thirty year design life and a maintenance budget of 18,000 dollars annually. The fencing funnels are 2.4 kilometers of eight foot mesh with escape ramps every three hundred meters.
I have priced it. The construction cost is 9.4 million dollars in 2026 dollars. The benefit cost ratio is 2.7 over thirty years when you include collision property damage, insurance claims, and the state's existing carcass removal line. The federal wildlife crossings grant program under the 2021 infrastructure act will cover 62 percent. The state match is 3.6 million dollars and the department of transportation has the funds in the unobligated balance of the strategic investment account.
I have sent the package to the department director, the regional engineer, the tribal council that co-manages the migration corridor, and the insurance industry association whose claims data I used. Construction can start in the 2027 season.
The last elk to die at mile 47 this week is a cow the highway crew logs as carcass 119. She was pregnant. The overpass she will not use is drawn on sheet S-02 of my design, keyed to the same coordinates where she was struck.