CDOT Begins Construction of First Wildlife Underpass on US 160 Between Durango and Bayfield

June 23, 2015 - Southwestern Colorado/CDOT Region 5 - LA PLATA COUNTY – The Colorado Department of Transportation is beginning a project to construct a wildlife underpass at US 160 at Dry Creek.

LA PLATA COUNTY – The Colorado Department of Transportation is beginning a project to construct a wildlife underpass at US 160 at Dry Creek, about five miles east of the junction with SH 172 (between MM 97 and MM 98). CDOT’s contractor for the project, Crossfire LLC, began mobilizing equipment to the site on June 19, yet impacts to travel will remain minimal through this project. The total cost of the project—from design through construction—is estimated at $6.5 million. The project will be completed in May of 2016, with a winter suspension of work likely from November 2015 through March 2016 (weather permitting).

The project constructs a large mammal underpass—a pre-cast concrete arch structure with a natural earth bottom. This arch span bridge will be and 37 feet wide and 13 feet high/tall. Crews will construct a paved, two-lane detour on which two lanes of traffic will travel during construction of the first half of the underpass; two lanes of traffic will then be switched onto the existing alignment while the other half of the arch span bridge is under construction.

Once construction is complete, the detour alignment will be fenced off but will remain in place to accommodate future widening from two to four lanes, as called for in the US 160 Environmental Impact Statement or EIS. The roadway above the underpass will remain a single lane in each direction with widened 10-foot shoulders. Crews will install some 10,700 linear feet of wildlife fencing and eight wildlife escape ramps.

Between 9,200 and 9,600 vehicles travel this stretch of US 160 each day,” CDOT Program Engineer Ed Archuleta said. “Crash data over the last five years show that 58 percent of all collisions are wildlife-vehicle crashes at this location. Reports also show a high number of single-vehicle overturning crashes are occurring here. The underpass and wider highway shoulders will help prevent these types of collisions.”

La Plata County tops the list for highest WVCs in the state at 252 in 2013; Jefferson County, 248; El Paso, 201; Douglas, 199; Garfield, 128; Moffat, 116; Larimer, 106; Montezuma, 106;  (please see more county- and statewide data, here: (Numbers above came from the chart entitled “Reported Wildlife-Vehicle Collisions by Type and County.”)

This underpass is the first of 24 large-mammal crossings recommended in the US 160 EIS between Durango and Bayfield. In addition, small mammal crossings are recommended every 1,000 feet. Wildlife features were identified in the EIS in coordination with Colorado Parks and Wildlife.

“Wildlife-vehicle collisions still remain one of the leading threats to the state’s wildlife, particularly during fall and spring migration” Colorado Parks and Wildlife Communications Manager Matt Robbins said. “We know where the migration corridors are and we work closely with CDOT to design mitigation features where they will be the most effective.”

PROJECT IMPACTS/INFORMATION:  Work will be done between 7 a.m. and 7 p.m. each day, though much of it will be accomplished off the highway and with the use of the detour. Lane closures are not anticipated until the end of the project, when the new alignment is tied to the existing. Once construction gets underway, the speed limit will be reduced to 40 mph during work hours. For more information or to ask questions, please contact the contractor’s public information line at (970) 828-2897.

NOTE FOR ONLINE WILDLIFE CHART INTERPRETATION: On CDOT’s Wildlife on the Move media page, there is a chart entitled “Reported Wildlife-Vehicle Collisions by Type & County;” the acronyms mean the following:  PDO = property damage only; INJ = injury accident; FAT = fatal accident. Please note, the numbers indicate the number of accidents involving a PDO, injury/ies or fatality/ies. So a FAT of “3” or INJ of “3” for example does not indicate that 3 people died or were injured that year, but rather there were three wildlife-vehicle collisions where a human fatality or injury (or several fatalities or injuries) occurred.

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Wildlife Crossings on Colorado state highways - below.

US 160 at Dry Creek, five miles east of SH 172; site of wildlife underpass


Some of the crossings (as noted) listed below were actually retrofitted culverts or existing bridges that, with fencing to guide the animals, now serve as wildlife crossings. The others were built specifically for wildlife crossing.


SH 9 between Silverthorne and Green Mountain Reservoir, Summit County – two crossings:  one for large mammals, the other for medium

I-25 south of Colorado Springs, El Paso County – three crossings:   concrete box culverts built primarily for drainage, but now with fencing will accommodate large mammals

US 40 Berthoud Pass, Grand County – three crossings:  two are designed for small/medium mammals, including lynx, the other is for large mammals

US 40 Muddy Pass, Grand County – two crossings:  one for medium mammals, the other for large

I-70 west of Glenwood Springs, Garfield County – seven crossings between mile posts 87 and 110:  interstate bridges, as well as concrete box culverts built primarily for drainage, now with fencing to guide large mammals

US 160 Wolf Creek Pass, Mineral County – two crossings:  both small/medium mammals, including lynx

US 160 west of Durango, La Plata County – one crossing:  built for large mammals

US 285 near Conifer, Jefferson County – one crossing:  built for large mammals

US 550 north of Ridgway, Ouray County – one crossing:  built for large mammals

US 550 south of Durango, La Plata County – three crossings:  one for large mammals near the New Mexico state line and two near CR 302, close to Durango, for small mammals

US 160 west of Durango, La Plata County – one large mammal underpass, originally constructed as a cattle pass.

To be constructed:

US 160 east of Durango, La Plata County – one large mammal underpass under construction during the summer/fall of 2015.

SH 9 south of Kremmling, Grand County, north Summit County - five underpasses are being constructed:  three will be complete in 2015 and two in 2016. Two overpasses will also be constructed:  one in 2015 and one in 2016.

There are additional small mammal crossings statewide that have either been newly constructed or retrofitted during highway projects.