Colorado DOT Breaks Ground on US 550-US 160 Connection South

DURANGO, CO — The Colorado Department of Transportation (CDOT) has begun construction of the US 550-US 160 Connection South. The project will complete the US Highway 160 interchange by connecting the existing bridge over US 160 to US 550 to the south. CDOT will construct this project using the design-build process, partnering with a contracted team led by Lawrence Construction Company and RS&H, Inc. The interchange is scheduled for completion by the spring of 2023.

CDOT Executive Director Shoshana Lew praised the collaboration and innovation among the partners involved with the planning and development of the project, which has garnered support from local, state, and federal governments.

“The list of local agencies investing in this project is quite impressive,” Lew said. “The City of Durango, La Plata County and the Southern Ute Indian Tribe have all stepped forward to make a commitment to the project's success. Colorado's Transportation Commission and Department of Local Affairs have also provided funding. And most significant is the successful $12.3-million federal FASTLANE grant award sought after by La Plata County.”

The total cost of the project is $98.6 million (this includes the total of both CDOT project management and the contractor award).

“Director Lew referred to the innovations in regard to funding. The design and construction of this project will also be built with innovation as a key component,” CDOT Region 5 Transportation Director Mike McVaugh said. “The construction team was chosen and awarded this contract because of their ideas and innovation on minimizing impacts to the environment, residents, and businesses in the area, while maximizing the project scope.”

Significant Additions, Savings, Through Design-Build Process

The initial scope of the project would have constructed a new 1.1-mile, four-lane section of US 550 north of La Plata County Road 220 to connect the major highway with the existing US 160 interchange. By using the design-build process the contractor was able to stretch funding, which allowed for the widening of an additional 3.3-mile section of US 550 south of CR 220 to four lanes, tying into the existing four-lane highway at the CR 302 intersection.

The work will involve the following key construction steps, which include several notable innovations designed by the contractor team to dramatically reduce construction impacts for the traveling public. With regard to the design-build process, some elements of these key steps are likely to evolve as the work progresses.

The project construction team will:

• Build a construction access road north of CR 220



• Construct a 600-foot bridge over Gulch A



• Construct a 250-foot bridge over Gulch B



• Begin excavation of what will amount to 1.2 million cubic yards of material along the new alignment



• Construct a two-lane roundabout connecting to the existing interchange bridge over US 160 



• Construct an 800-foot long, 20-foot high soil-nail retaining wall adjacent to what will be the new US 550 northbound alignment



• Construct the new four-lane alignment between CR 220 and the existing interchange bridge over US 160



• Construct up to 32 small mammal crossings under US 550 



• Construct two large mammal crossings under what will become the new US 550 alignment south of CR 220



• Construct 3.3 miles of US 550 south of CR 220



• Construct new access roads and/or driveways — all with deer guards — into residences and businesses



• Construct approximately eight miles of eight-foot-tall wildlife fencing, including wildlife escape ramps



• Remove and revegetate the old US 550 alignment down Farmington Hill

By realigning US 550 to connect with the US 160 interchange in Grandview, the project will enhance safety for passenger and commercial vehicles, as well as cyclists. The new connection will eliminate the steep, curved grade of the current US 550. This realignment will improve safety by creating a full-service, continuous-flow interchange that eliminates signalization and at-grade intersections where crashes can occur. Safety will also be improved through the widening of US 550 to four lanes, with widened shoulders and auxiliary lanes for safer merges onto and off of the highway. Finally, the project will increase safety through wildlife underpass crossings and deer fencing, which will reduce animal-vehicle collisions.