Boulder County is collaborating with the Colorado Department of Transportation and Colorado Parks and Wildlife to develop plans for a comprehensive wildlife crossing system along US 36 between Boulder and Lyons. Plans will include structures, such as overpasses and underpasses, to improve motorist safety and maintain wildlife connectivity.
US 36 Wildlife Crossings
Take the Survey
Let us know what you think about proposed wildlife crossings by taking a two question survey. Your feedback will help determine the future of the project.
Action Needed
Reducing the number of vehicle-related wildlife accidents on US 36 between Boulder and Lyons has been a longstanding priority. This was further affirmed by the Eastern Slope and Plains Wildlife Prioritization Study (ESPWPS) in April 2022. The report was conducted for the Colorado Department of Transportation and Colorado Parks and Wildlife and outlines regional priorities and recommended actions aimed at decreasing wildlife-vehicle collisions.
Top 5%
The section of US 36 between Boulder and Lyons (emphasis on Nelson to St. Vrain) was rated in the top 5% and has the highest prioritization score in Region 4. This is based on modeling that includes wildlife-vehicle collisions, deer/elk density of winter range use, deer/elk migration routes, traffic volumes overall, and distance from suburban housing density.
10x Higher
Wildlife strikes average 3.2 animals per mile/per year which is more than 10 times higher than the rest of Boulder County, which averages .26 strikes per mile/per year.
Damages
The human cost of wildlife collisions is significant. Each accident typically costs drivers $11,100 in property damages and over $101,000 if injured.
Crash Data
Traffic crash data from 2009-2018 shows wildlife-vehicle collisions are most numerous on US 36 between Boulder and Lyons.
Conceptual Wildlife Crossings
Boulder County is considering several different wildlife crossing structures including overpasses, underpasses, and wildlife fencing. The exact designs have not been finalized and the images below are ideas being considered.
Conceptual design of an underpass crossing under US 36
Conceptual design of an overpass crossing with a separated bike lane looking north
Conceptual design of an overpass with a separated bike lane looking northeast
Conceptual design of an overpass with a separated bike lane looking southwest
Potential Locations from ESPWPS
- All highway segments ranked in the top 5% of the Eastern Slope and Plains Wildlife Prioritization Study (ESPWPS) were further assessed in person.
- Consultants examined the surrounding topography to identify suitable locations for wildlife crossings and assessed whether existing infrastructure could be modified to accommodate these crossings.
- Six areas were identified as potential wildlife crossings and one existing structure could be improved.
North Foothills Bikeway Project
The North Foothills Bikeway is a proposed biking and walking path along US 36 between Boulder and Lyons. Planners are coordinating the bikeway and wildlife crossings so the designs align and neither project adversely affects the other.
Wildlife Movement
Due to the variable topography along US 36, the bikeway will require barrier walls, cut-and-fill slopes, separated shoulders, railings, and other structures that can impede movement of both small and large animals.
Environmental planners Dudek, ECO-Resolutions, and WSP have been hired to assist with the project. They are experts in road ecology and understand how roads affect natural systems and wildlife movement. The teams will incorporate wildlife-friendly design measures where feasible, such as lowered barrier heights, live-bottomed culverts, and non-hardened slopes.
Safety for All
By aligning these parallel initiatives, the project teams are working to deliver infrastructure that safely and effectively meets the community’s needs and improves wildlife connectivity. The teams refer to this combined effort as “Safety for All,” reflecting goals to improve safety for motorists, cyclists, pedestrians, and wildlife in this deadly corridor.
CU Student Researchers
Student researchers from the University of Colorado Boulder Masters of the Environment program are conducting frequent roadkill surveys on foot along US 36 and will deploy remote cameras this summer. Their data will help the project team identify problem areas along the corridor, especially smaller-animal collisions that are often underreported, and increase understanding of animal movements.
Funding
Grant funding will be essential for the completion of the project. Boulder County will actively pursue various federal and state grant programs to secure the necessary funding.
- America the Beautiful Grant: The National Fish and Wildlife Foundation (NFWF) provides grants aimed at the development of large-scale, locally led projects spanning public and private lands. Priorities include connecting and reconnecting wildlife corridors, large landscapes, watersheds, and seascapes.
- The Wildlife Crossing Fund: Recently partnered with private and public entities to secure $500 million dollars towards wildlife crossings.
Previous Public Meetings
Oct. 22, 2024 – Audubon Society
Staff presented information about the project to the Boulder County Audubon Society.
Video
Aug. 7, 2024 – Information Meeting
Staff presented information about the project. Attendees were able to ask questions and share concerns.
May 15, 2024 – Society for Ecological Restoration
The Society for Ecological Restoration-Rocky Mountain’s group of restoration-minded professionals held a panel discussion about all things wildlife crossing and the importance of implementing these projects from wildlife connectivity and transportation safety perspectives.
Panelists included:
- Ben Goldfarb, Environmental Journalist
- Julia Kintsch, Senior Ecologist at Eco-Resolutions
- Susan Spaulding, Wildlife Biologist at Boulder County
April 25, 2024 – Parks & Open Space Advisory Committee
Staff introduced the project to the Parks & Open Space Advisory Committee.
Staff Memo
Video
Partner Support
The project has the support of the following agencies and organizations:
- Colorado Parks and Wildlife
- Colorado Department of Transportation
- University of Colorado Boulder Masters of the Environment
- Local municipalities
Additional Resources
- US 36 Wildlife Crossings Project Memo to Board of County Commissioners (April 2024)
- US 36 Wildlife Crossing Assessment, Prioritization, and Cost Estimation Study (Aug. 2024)
- Frequently Asked Questions About Wildlife Crossings (ARC Solutions News)
- How wildlife crossings protect both animals and people (CBS News)
- Colorado is becoming a leader in constructing wildlife crossings (Denver 7)
Contact Us
Parks & Open Space
Susan Spaulding
Environmental Resources Specialist
sspaulding@bouldercounty.gov
