State Highway 9 Wildlife Crossings Monitoring Research

In 2015 and 2016, Colorado’s first two wildlife overpasses, five wildlife underpasses, wildlife exclusion fencing, and other mitigation features were constructed on State Highway 9 between Kremmling and Green Mountain Reservoir in the north-central Colorado Rocky Mountains. ECO-resolutions led a five-year research study to evaluate the effectiveness of the mitigation in reducing wildlife-vehicle conflict while maintaining connectivity for wildlife.

The study established that the mitigation investments on SH 9 resulted in a 92% reduction in wildlife-vehicle collisions crashes and a 90% reduction in carcasses. In addition to improving safety for motorists, the study demonstrated the success of the crossing structures in maintaining connectivity for mule deer across SH 9 for all age and gender classes of the population. The research documented 112,678 mule deer successful passages across the seven structures, with an overall success rate of 96%. The study also established the value of the wildlife crossing structures and other mitigation for a number of other species, including ungulates, carnivores, and other medium-sized and small mammals. The research documented the effectiveness of escape ramps, wildlife guards, and the fence end design and provided recommendations for future mitigation projects. This study demonstrated the success of the SH 9 wildlife crossing structures and other mitigation for both wildlife and motorist safety. The findings of this study and resulting recommendations will help transportation and wildlife agencies continue to site and design wildlife crossing mitigation for maximum success.