Greenland Overpass - Wildlife Crossing Pilot Program 2023

Colorado

Road: Interstate 25 - South of Denver (between Castle Rock and Monument)

Structure: One new overpass

Target Species: Primarily elk, but also deer, pronghorn, black bear, mountain lion and small animals

In 2023, the Colorado Department of Transportation (CDOT) was awarded $22 million from the Federal Highway Administration’s  Wildlife Crossing Pilot Program  (WCPP) to construct one new wildlife overpass. The overpass will be located on I-25 at milepost 165.4 between Denver and Colorado Springs—Colorado’s two most populous cities—and will be the final stage of the  I-25 South Gap Wildlife Crossing Project . Four dedicated wildlife underpasses and one shared-use pedestrian and wildlife underpass were constructed in 2021 as part of a larger transportation project that widened 19 miles of I-25. 

Design for the overpass began in January of 2022 and was completed in March of 2023. The $22 million in WCPP funds was awarded in December 2023, completing fundraising for the $30 million overpass. The additional $8 million dollars came from CDOT ($7.5 million) and The Colorado Wildlife and Transportation Alliance via state Senate Bill 151: Safe Crossings for Colorado Wildlife and Motorists ($500,000). Additional contributions came from Douglas County, who contributed $75,000 for preliminary design of the overpass as well as the Douglas Land Conservancy which granted CDOT a permanent easement for the overpass on the west side of the highway at no cost. Construction is expected to begin in late 2024 or early 2025. From 2017 to 2018, pre-construction monitoring took place via 13 game cameras at 23 locations across 14 miles to determine where to locate crossings. The overpass will cross six lanes of interstate highway, have a width of 200 feet and a length of 209 feet, making it one of the largest overpasses in North America. The structure will tie into the existing 8-foot-high wildlife exclusion fencing that was constructed between all five underpasses in 2021. 

The overpass will be built along a scenic, high-elevation stretch of I-25 in Colorado—7,115 feet. The 78,000 vehicles that drive this section daily often experience inclement weather as well as wildlife on the road as the highway cuts between foothills habitats for large mammals like elk, mule deer, pronghorn, black bears, and mountain lions. Prior to construction of the underpasses in 2021, 10% of traffic delays in this area were due to wildlife-vehicle collisions. Post-construction monitoring of the underpasses is ongoing, and many animals have  already been documented using them  such as elk, deer, bear, bobcats and many smaller mammals, amphibians and birds. The overpass will be a welcome addition, particularly for elk and pronghorn, who strongly prefer using overpasses, rather than moving through noisy and relatively dark underpasses. However, this project has seen some success passing elk with the larger underpasses; thus continuing to advance the science of wildlife underpasses. The overpass will also be monitored following structure completion.

The Greenland Overpass is being constructed as a result of years of collaborative work among many partners including: U.S. Department of Transportation, Federal Highways Administration, CDOT, Colorado Parks and Wildlife, Douglas and El Paso Counties, Pikes Peak Regional Transportation Authority, Colorado Wildlife and Transportation Alliance, Colorado Cattlemen’s Agricultural Land Trust, and Douglas Land Conservancy. 

LEARN MORE

Video about the overpass grant:  Wildlife crossing planned over I-25 in Colorado  

Acknowledgements

Thank you to Brandon Marette and Lexi Hamous-Miller (Colorado Parks and Wildlife), Chuck Attardo (Colorado Department of Transportation) and Andy Hough (Douglas County Open Space) for contributing content and technical review of project information.

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