Business Center

A Safe Crossing: Colorado’s collaborative research project for wildlife-vehicle mitigation

By Mary Nordini, Process Improvement Intern

July 8, 2019

Between mile markers 126-136 on State Highway 9 in Grand County you will see some eight-foot fencing and even two grassy bridges spanning the road—ever wonder what these are?


These structures are part of a larger research project that is being conducted in an effort to prevent wildlife-vehicle collisions (WVC). It began with a safety improvement project to widen the shoulders, remove dangerous bends, and add wildlife safety measures due to the high collision rates. In a collaboration between the Colorado Department of Transportation, Colorado Parks and Wildlife, and ECO-resolutions, a five-year study was initiated in 2015 to assess the effectiveness of these preventative methods.


Overall this is a major project, with Colorado’s first two wildlife overpasses, five underpasses, ten miles of exclusion fencing, 61 escape ramps and 20 deer guards all monitored by over 60 full time cameras. With the wide scope of the project, Colorado Parks and Wildlife stepped up to supplement some of CDOT’s funding and contribute staff hours to help with the study, while ECO-resolutions provided the study design and analysis of data.

Talking with the research project manager, Bryan Roeder, this project is unique in its success and approach. “Typically, when you build structures like that, for deer and elk, it takes a few years for them to acclimate to it and start using it. But they started using those right away. So it's shown good results right away.”

And what are those results? Within the first two years of the study, the data showed a clear decreasing trend in WVC after installation of the preventative structures. There was an 89% reduction in WVC post construction compared to the 5 year pre-construction average of 56.4 collisions. Principal investigator Julia Kintsch, of ECO-resolutions, has been excited by the project, getting to watch the movements of different species. She reports, “really phenomenal use by mule deer, with 45,000 crossing, all varying in age and gender. There are multiple occurrences where a doe is accompanied by her fawn, crossing the structures and demonstrating that they are teaching the generations to use these structures, which is really promising in restoring connectivity and continued use.”

There are diverse species seen using the structures as well, in low numbers, however this is not a major concern to the research panel. Elk are known to be slow in adapting to new habits, however there has been documented usage of the structures. Additionally elk have been observed to move in a north to south direction, indicating no strong drive to use the structures. Black bears, including sows with cubs, have used the underpasses, assumingly when they are located within the bear’s territory. The occasional moose cow and calf, or stray pronghorn have also been seen. These results support the effectiveness of these wildlife structures mitigating WVC along this stretch of SH9.

Not only was there immediate success, but the ongoing nature of this project enabled the team to work with more data. They started research before construction, providing a full scope of the situation and results, and managing adaptively until construction was complete. Although projects of this nature are high in cost, the information provided through this research have allowed other projects to move forward, setting an example of effective mitigation efforts on the type of structures that work to reduce accidents while providing safe passage for wildlife and the public. CDOT biologist Cinnamon Levi-Flinn has supported the monitoring and species assessments on this project, and found this research beneficial in the development of a culvert expansion for wildlife mitigation on the Colorado-Wyoming border of State Highway 13. Not only has this research provided data to help some small scale projects, but it has been requested by other states in their consideration of wildlife mitigation projects.

What is next? They continue to study the success of the implemented methods, but have extended their monitoring to the end of the study area. Roeder assures, “Something that the people in this field are aware of, when you put up a fence, as long as you maintain it well, you're going to reduce accidents with wildlife, but they're just going to find the closest place they can go around.” The next steps are to ensure they have not just moved the problem of WVC to another area along this highway. Preliminary reports suggest WVC have not increased beyond the fence of the project area, though this continues to be monitored. The performance measures for project success regarding mule deer have been met, while hopes for further improvement from other species is expected from the remaining time of the study. At the end of the study and active monitoring there is hope that the accident rate doesn’t rebound back to high WVC, but only the last two years will tell. However this project has provided mitigating structures that can be used to protect the wildlife and beauty Colorado offers to travelers throughout the state. It is important to spread awareness, not only to the public on the great success these structures have had, but to other DOTs and departments of parks & wildlife to see data and examples of effective mitigation efforts. The structures are expensive, but they are proving to be effective and well worth the resources.