Frequently Asked Questions

General Information about Wildlife Crossings

    • Colorado: 70+ wildlife underpasses and 4 overpasses completed, with more planned

    • United States: Over 1,000 crossings have been built, including structures in Montana, Wyoming, Utah, California, Florida, Maine, and many other states.

    • World: Europe leads the way in terms of wildlife structures. The Netherlands alone has 600+ tunnels and overpasses for everything from hedgehogs to wild boar and Canada's Banff National Park has 44 structures (6 overpasses, 38 underpasses). France pioneered wildlife crossings in the 1950s.

  • Wildlife crossings are a proven strategy for reducing wildlife-vehicle collisions while also allowing animals to safely access the habitat and resources on either side of a road. Wildlife crossings physically separate wildlife movements from traffic by providing safe passages either under or over a road. Tall fencing directs animals to these passages while preventing them from getting onto the road. 

    Wildlife crossings are very effective!

    • On Highway 9 in Grand County:

      • A system of 5 underpasses and 2 overpasses along 10-miles of fenced highway reduced collisions by 92% and were used by 17 species of large and medium-sized mammals.

    • On Interstate 25 in Douglas County: 

      • 5 large bridge underpasses and 14 miles of fencing reduced wildlife-vehicle collisions by 85% in the first two years post-construction. 

      • The crossings provide passage for mule deer, elk and many other wildlife, including small mammals, amphibians, and reptiles. 

      • The recently constructed Greenland Overpass completes the mitigation system and is expected to allow even more wildlife to cross the interstate to access vast open space lands on either side while further reducing collisions. 

    These are just a few examples in Colorado. Across western states and around the nation and the globe, wildlife crossings are being used to reconnect landscapes, support long-distance migrations, and facilitate wildlife movements across landscapes that have been fragmented by roads, development, and other infrastructure. 

  • Wildlife crossings are highly effective when combined with proper fencing. Studies show:

    • Colorado's Highway 9 project reduced crashes by 92% 

    • Canada's Banff National Park crossings led to an 80% reduction in wildlife-vehicle incidents, with common species such as deer and elk reduced by 96%

    • Wyoming's Trapper's Point project reduced wildlife-vehicle collisions by 80% in the first three years

    • Montana's Highway 93 crossings reduced collisions with wildlife by over 70%

    The key to effectiveness is combining overpasses and underpasses with fencing systems that guide animals toward safe crossing points rather than onto the highway.

  • Fencing is essential to the success of wildlife crossings:

    • Guides animals: Directs wildlife away from dangerous highway sections toward safe crossing structures

    • Prevents access: Keeps animals off the roadway between crossing points

    • Maximizes effectiveness: Crossings combined with fencing reduce collisions by 87-97%, versus lower effectiveness without fencing

    • Multiple components: Complete systems include:

      • Wildlife fencing along roadways (typically 8 feet tall)

      • Escape ramps for animals that exploit a gap and get trapped on the wrong side of a fence

      • Wildlife guards at access points (driveways and road intersections)

    Examples:

    • Colorado Highway 9: 10.3 miles of fenced highway  with 29 wildlife guards and 61 escape ramps

    • I-25 Gap project: 14 miles of fenced highway with 5 large wildlife underpasses, 1 overpass, 63 escape ramps and abundant wildlife guards. 

    • Wyoming's Trapper's Point: 12 miles of fenced highway with 6 wildlife culverts/underpasses

  • Location selection involves multiple scientific factors:

    • Wildlife movement data: GPS collar data, trail cameras, aerial reconnaissance, and migration pattern studies

    • Collision history: Areas with high rates of documented wildlife-vehicle collisions

    • Habitat connectivity: Locations that connect high-quality habitats on both sides of the highway

    • Road characteristics: Areas with high traffic volume, high speeds, and road design challenges

    • Landscape features: Natural drainages  and habitat corridors where animals already cross

    • Protected land: Areas with surrounding open space or conservation land to maximize long-term benefits

    • Development pressure: Locations where opportunities to reconnect habitat still exist (before development closes them)

  • The Western Slope Wildlife Prioritization Study (WSWPS) is a valuable tool, but it does not tell the whole story of the Roaring Fork Valley’s need—and the agencies that produced it have said as much.

    The study evaluated highway segments across two broad categories: safety and crash patterns (approximately half the weighting) and wildlife movement, collision risk, and population-level mortality impacts (approximately half the weighting). Both categories are legitimate and important, and the study was built on the best available data at the time of its completion.

    The primary reason the Roaring Fork Valley did not rank higher is not a reflection of low actual risk: wildlife-vehicle collision data from this corridor has historically been under-reported in the statewide crash database. Pitkin County Sheriff’s Office is now submitting WVC crash reports directly to the state to ensure future analyses reflect the true scope of the issue here. It is also worth noting that no prioritization study can place every high-need segment in its top tier—by definition, not every segment can rank in the 95th percentile. The study was designed to guide statewide agency-led efforts, not to serve as the sole determinant of which communities could or should act.

    The Highway 82/133 study conducted by Roaring Fork Safe Passages in partnership with local agencies provides a valid, actionable, and locally-grounded analysis of the valley’s specific needs. It is consistent with the data that does exist in state databases and is supported by extensive GPS collar data, trail camera documentation, and a decade of local collision records.

    CDOT and CPW have demonstrated a clear willingness to partner on projects that fall below the 95th percentile threshold when local need, partnership strength, and community support are compelling. The I-70 East Vail Pass project is a prominent example: it ranks in the 62nd percentile on the statewide prioritization study—well below the top tier—yet it is one of the Colorado Wildlife and Transportation Alliance’s six highest-priority funding targets, because it demonstrates documented connectivity need, broad partnerships, and strong community backing. The Roaring Fork Valley presents an equally compelling case.

    Across Colorado, local communities are stepping up to address wildlife connectivity and WVC reduction. This is not a workaround—it is how many of the state’s most successful crossing projects have come to exist. CDOT and CPW have explicitly recognized that the need for crossings extends beyond what agencies can address independently, and that community-led partnerships allow far more projects to move forward than would otherwise be possible. Our locally-driven effort is a model of this approach, not an outlier to it.

  • The timeline varies significantly depending on project complexity:

    • Planning and design phase: Can take at least 2-5 years to identify locations, secure funding, complete environmental studies, and finalize engineering designs

    • Construction phase: Typically 1-2 years once funding is secured 

    • Notable example: Colorado's I-25 Greenland overpass was completed in less than a year, ahead of schedule—though this is considered exceptionally fast for large infrastructure projects

    • Total timeline: From initial concept to completion, most projects take 3-10 years, however some take 20 years to realize

    It's important to note that identifying the best locations and securing funding often takes longer than the actual construction.

  • Several factors make immediate action critical:

    • Development pressure: As the valley continues to develop, wildlife corridors are at risk of being severed, making wildlife populations less resilient.

    • Traffic growth: Traffic on Highway 82 is projected to reach 26,400 vehicles per day by 2045, making the problem worse and creating a major barrier to wildlife movements.

    • Limited opportunities: Land protection and corridor preservation opportunities won't be available indefinitely—once development closes these corridors, they're lost forever

    • Declining elk & deer populations: Elk and deer populations are already declining in Pitkin and Eagle Counties due to a multitude of impacts from development, roads, and recreation, with elk calf recruitment below objective in both local herds

    • Increased moose populations: Colorado’s moose population has grown by more than 50% over the past two decades with moose crashes being about ~18x more likely to be fatal than deer crashes. 

    • Strategic investment: Building now prevents worse problems and higher costs later

Funding, Costs & Financial Impacts

  • Click to View Image of Cost-Benefit Analysis

    Based on data from the U.S. Bureau of Labor Statistics (BLS) through December 2025/January 2026, the consumer price index (CPI) for all items has risen approximately 25% since January 2020.

  • Costs vary significantly based on terrain, size, and complexity:

    • Wildlife underpasses: Generally less expensive, can range from a few hundred thousand to several million, depending on the underpass size and focal species

    • Wildlife overpasses: $5-30+ million

    • Complete systems: Colorado Highway 9 project (2 overpasses, 5 underpasses, fencing): total system cost ~$46-50 million in 2015/16

    • US 160: $12 million in 2022

    • I-25 Greenland overpass: $23 million in 2025 

    • Roaring Fork Upper Valley estimates: $22.4-32.5 million for first two structures; $34.5-50 million for additional three structures. These estimates include fencing and other associated mitigations (e.g., deer guards at road access points and escape ramps)

    However, the economic case for wildlife crossings is strong: collisions in Colorado cost approximately $313 million annually, and crossings reduce collisions by 87-97%, often paying for themselves within 17-20 years.

  • Annenberg Wildlife Crossing

    FUNDING BREAKDOWN

    Private: ~$54-60 million (60%)

    • Annenberg Foundation: $26 million (largest single donor)

    • Leonardo DiCaprio Foundation: Amount undisclosed

    • 6,000+ individual donors via #SaveLACougars campaign: ~$28-34 million

    Public: ~$36-40 million (40%)

    • California Wildlife Conservation Board: $25 million

    • State of California: $20 million

    • Congressman Ted Lieu (Federal): $2.5 million

    • California Coastal Commission: $1 million (environmental assessment)

    • California Wildlife Conservation Board: $650,000 (design grant)

    • Additional state/federal sources: Balance 

    Total Project Cost: ~$90-100 million

    Colorado State Highway 9 Project 

    FUNDING BREAKDOWN

    Public (State): ~$37-40 million (80%)

    • Colorado Department of Transportation RAMP (Responsible Acceleration of Maintenance and Partnerships) program: Majority funding

    • Selected for RAMP fast-track in October 2013

    Private/Local: ~$9-10 million (20%)

    • Paul Tudor Jones (Blue Valley Ranch owner): $4 million matching grant + additional $1 million = $5 million total (single largest donor)

    • Grand County: $3.1 million 

    • Summit County and local municipalities : (~$1-2 million)

    • Small individual donors: Contributions from across the United States

    Total Project Cost: ~$46-50 million

    U.S. Highway 160 Wildlife Crossing (Durango-Pagosa Springs)

    FUNDING BREAKDOWN

    Public (State/Federal): ~$10.5 million (93%)

    • Colorado Department of Transportation: $8.6-9.5 million

    • Colorado Parks and Wildlife: $750,000 (plus studies and research)

    • National Fish and Wildlife Foundation: $317,000

    Private/Tribal: ~$0.8-1.5 million (7-13%)

    • Southern Ute Indian Tribe: $1.3 million (plus critical GPS data on migration patterns)

    • Mule Deer Foundation (private donor): $100,000 (in memory of Glen E. Grush, Bayfield, CO)

    • Rocky Mountain Elk Foundation: $75,000

    Total Project Cost: ~$11.3-12 million

    Colorado’s 1-25 Greenland Overpass

    FUNDING BREAKDOWN

    Public (Federal): ~$22 million (73%)

    • Federal Wildlife Crossing Pilot Program: $15 million

    Public (State/Local): ~$8 million (27%)

    • Colorado Department of Transportation: Portion of $8 million

    • Colorado Wildlife & Transportation Alliance (via Senate Bill 22-151): $500,000

    Total Project Cost: $30 million (under budget)

  • Wildlife crossings provide multiple economic benefits:

    • Wildlife economy: Wildlife-related activities (wildlife viewing, fishing, hunting) generate $10.23 billion annually in Colorado—MORE than winter resort activities ($8.25 billion) and MORE than the ski industry! Protecting wildlife populations through crossings helps sustain this critical economic sector.

    • Reduced collision costs: Save millions in vehicle repairs, medical expenses, emergency response, and lost income

    • Insurance savings: Fewer claims and lower insurance premiums over time

    • Tourism and recreation: Protect wildlife populations that support Colorado's $65.8 billion outdoor recreation economy

    • Hunting industry: Support healthy wildlife populations for Colorado's $843 million hunting industry

    • Quality of life: Preserving wildlife populations and reducing collision risks enhances residents' quality of life—a core community value that strengthens the valley's appeal and long-term economic vitality

    • Return on investment: Crossings often pay for themselves within 17-20 years through reduced collision costs alone

    • Roaring Fork Valley: In the Roaring Fork watershed, wildlife-vehicle collisions are the leading cause of crashes reported to law enforcement. Along the 12-mile stretch between the Aspen/Pitkin County Airport and Aspen Village alone, there have been more than 450 documented wildlife-related crashes over the past decade. Between 2014-2023, 55% of all collisions in this area involved wildlife, with 34% specifically caused by elk.

    • Colorado: 7,163 carcasses collected in 2023 (CDOT official count), but actual estimates are closer to 14,100-20,000 annually due to underreporting. In northwest Colorado alone: 2,389 animals reported killed in 2023

    • United States: 1-2 million large animal collisions annually, resulting in approximately 200 human deaths and 26,000 injuries

    In the United States deer vehicle collisions amount to 1.5-2.1 million annually resulting in 26,000-59,000 injuries and approximately 200-440 human fatalities per year (Sharma et al. 2025). 

  • Highway 82 ranks in the top 8 most dangerous roads in Colorado when it comes to wildlife collisions, according to Colorado Parks & Wildlife. The 6-mile stretch between the Aspen/Pitkin County Airport and Cozy Point experiences an average of 5.6 wildlife-vehicle collisions per mile per year, with 55% of all reported accidents on this segment involving wildlife. CDOT has officially identified this segment as a wildlife-vehicle collision hotspot.

  • The data on this corridor is unambiguous. To understand its scale, it helps to compare the Airport–Aspen Village segment to both the rest of Highway 82 and to statewide averages

    • 55% of all crashes on the Airport–Aspen Village segment involve wildlife

    • 27% of all crashes on the broader Glenwood Springs–Aspen corridor involve wildlife

    • 3.2% of crashes statewide involve wildlife (10-year annual average)

    Put simply: wildlife-vehicle collisions account for more than half of every reported crash on this segment—roughly 17 times the statewide rate.

    The segment’s share of county-wide collisions is equally striking:

    • The Airport–Aspen Village segment accounts for 24% of all wildlife-vehicle collisions in all of Pitkin County.

    • It accounts for 58% of all elk-vehicle collisions in the county—on just six miles of road.

    • 11% of wildlife-vehicle collisions on this segment result in injuries to humans.

    More than half of all elk-vehicle collisions in the entire county occur on a stretch of highway less than six miles long. Colorado Parks & Wildlife has identified Highway 82 (Glenwood Springs to Aspen) as one of the state’s high-risk corridors for wildlife-vehicle collisions, and drivers are specifically cautioned to exercise additional care along this route (cpw.state.co.us/wildlife-collisions).

    Wildlife crossings combined with fencing have been shown repeatedly to reduce collisions by 85–97% at comparable hotspot sites across Colorado and the West. Applied to the Airport–Aspen Village segment, which currently sees an annual average of 16.7 wildlife-vehicle collisions per year, crossings and fencing would be expected to reduce that figure to approximately 1.7 to 2.5 collisions per year. That is a transformation in safety, not an incremental improvement.

  • By 2045, traffic on Highway 82 is projected to increase 32%—from approximately 20,000 to 26,400 vehicles per day—potentially proportionally increasing wildlife collisions. Combined with ongoing development pressure, this creates a compounding crisis for valley wildlife.

    The situation is already critical. Elk and deer populations are declining in Pitkin and Eagle Counties, with elk calf recruitment critically low at the mid-30s per 100 cows when sustainable growth requires 60-70. Highway 82 already blocks access to critical winter range and breeding habitats, and without crossings, higher traffic volumes will make the road an impassable barrier.

    When herds can't intermingle, genetic isolation in a population increases, reducing disease resistance and long-term viability. In addition, animals lose access to winter range, summer feeding areas, and breeding territories. Research shows that fragmented landscapes support 12% fewer species than connected habitats, amplifying these impacts.

    Without wildlife crossings, projections could lead to additional decline in local elk herds beyond current trends by 2045, with continued low calf recruitment preventing population recovery. 

  • Fall is generally the most dangerous season for wildlife-vehicle collisions. According to State Farm data, the months of October, November, and December account for an estimated 650,000 incidents nationwide—representing 41% of all animal collision claims for the entire year. This aligns with wildlife migration patterns and mating seasons when animals are most active and mobile. 

    Spring (March-May) is a secondary peak as animals move toward calving habitat and summer range.

  • Wildlife crossings near the Aspen/Pitkin County Airport provide an important aviation safety benefit. When animals are struck and killed near the runway, their carcasses attract large scavenging birds such as vultures and eagles. These large birds pose serious risks to aircraft during takeoff and landing. By reducing wildlife deaths near the airport, crossings help eliminate this aviation hazard and improve safety for passengers and pilots.

Vehicle Wildlife Collisions & Safety

Insurance Coverage

  • Short answer: About half of Colorado drivers—approximately 2.0–2.1 million people—lack insurance coverage for wildlife collisions. This burden falls disproportionately on lower-income residents.

    Coverage Basics

    Only comprehensive auto insurance covers wildlife collision damage. Colorado law doesn't require it, so many drivers carry only liability insurance or liability plus collision coverage—neither of which covers animal strikes.

    The Numbers

    • Total licensed drivers: ~4 million

    • Without comprehensive coverage: ~52% (~2.0–2.1 million)

    • Completely uninsured: ~16–17.5% (~650,000–700,000)

    Who Lacks Coverage?

    Research shows that comprehensive coverage gaps disproportionately affect lower-income communities. Vehicle owners with lower incomes and older cars are significantly less likely to purchase comprehensive coverage because:

    • It's optional and costs extra money beyond state-required minimums

    • Older vehicles may not justify the additional premium expense

    • Financial priorities focus on meeting other needs

    This creates an economic justice issue: drivers with the least financial resources face 100% out-of-pocket costs when wildlife collisions occur.

    Why It Matters

    Wildlife collisions can be financially devastating for uninsured or underinsured drivers. These costs fall entirely on individuals, not insurers—hitting lower-income households hardest.

    Note: These are best-available estimates based on state driver counts and insurance industry data, as Colorado doesn't publicly track policies by coverage type.

    While insurance companies track wildlife-vehicle collision costs (State Farm estimates 1.23 million deer-vehicle collisions annually costing over $4 billion in vehicle damage), they have not directly funded infrastructure projects to date. 

  • Beyond the statistics, animal welfare is also at stake:

    • Blunt trauma from vehicle strikes doesn't always cause immediate death—many animals suffer prolonged distress from internal injuries or broken limbs.

    • Unlike natural predation, vehicle collisions can indiscriminately kill healthy animals in their reproductive prime, affecting animals of all ages and capabilities.

    • Vehicle strikes don't contribute to natural ecological balance the way predation does.

    • Reducing wildlife trauma is a matter of basic humanity and aligns with community values.

    • Global: Wild mammals now represent only 4-5% of total mammal biomass (humans: 36%, livestock: 60%)

    • Wild terrestrial mammal biomass has declined by 85% over the past 100,000 years

    • Since 1850, combined wild land and marine mammal biomass has declined by approximately 70%

    • Roaring Fork Valley specific: Our estimates leave us at still 50/50 in our valley. Nature still has half here. 

    • Our land is protected unequally, with higher-elevation summer range habitats far more likely to remain free of extensive human impact, while lower-elevation winter ranges for many animals are more heavily developed.

  • The Roaring Fork Valley crossings are designed to accommodate multiple species:

    • Primary target species: Elk and mule deer (which account for the highest collision rates)

    • Large mammals: Black bears, moose, mountain lions

    • Medium-sized mammals: Coyotes, bobcats

    • Smaller wildlife: Various small mammals like racoons, fox, etc. 

    Different species prefer different crossing types: bears, and mountain lions tend to use underpasses, while elk prefer more open, expansive overpasses or large underpasses. Deer use both. The Roaring Fork projects will include both types to accommodate diverse wildlife.

  • Wildlife corridors are increasingly important for climate adaptation:

    • Habitat fragmentation limits wildlife's ability to respond to fire, drought, and extreme weather events

    • Animals need the flexibility to move to areas with better resources as conditions change

    • Highway 82 is the most continuous major barrier to wildlife movement in the valley, bisecting critical migration routes

    • Connected habitats allow animals to adapt their ranges as climate patterns shift

Wildlife & Ecosystem Conservation

Community Engagement & Support

  • The community has shown overwhelming support for wildlife crossings:

    • 95% of 730 survey respondents support the wildlife crossing structures

    • 85% believe it will improve their quality of life in the valley

    • Preserving wildlife is a core value identified in Pitkin County Vision 2050

    • Both Pitkin County and the City of Aspen have provided financial support 

    • The project has received strong nonpartisan support from local government and residents

  • The Colorado College 2024 Conservation in the West Poll shows overwhelming, bipartisan support for wildlife crossings, with 85% of Westerners favoring their construction over major highways. Among Colorado voters, support reaches 87%, with 78% prioritizing conservation of migration routes over development. 

    Key findings from the Colorado College State of the Rockies 2024 report include:

    • Strong Bipartisan Support: 79% of Republicans, 87% of Independents, and 89% of Democrats support building these structures.

    • High Priority: Voters consider the loss of wildlife habitat a serious issue and prioritize funding for wildlife crossings.

    • Regional Context: The survey spans eight Western states, reflecting a broad consensus on protecting wildlife migration and reducing vehicle collisions. 

    These findings indicate that wildlife connectivity is a uniting issue across the political spectrum in the Rocky Mountain West.

  • Community members can support Roaring Fork Safe Passages in several ways:

    • Stay informed: Visit roaringforksafepassages.org for updates and meeting schedules

    • Engage: Participate in community meetings and provide input

    • Contact elected officials: Express support to county commissioners, city councils, and state representatives

    • Report wildlife observations: Report wildlife crossing locations and collision hotspots by contacting us directly here: https://www.roaringforksafepassages.org/contact-us 

    • Financial support: Donate here: https://www.roaringforksafepassages.org/donate 

    • Spread awareness: Share information with neighbors, community groups, and on social media

    • Advocate for funding: Encourage local and state governments to provide matching funds that unlock federal grant dollars

References and Sources