Sterling S Curve Alignment on US 6, CO 14 & CO 138

Project Facts

  • Cost: $16.6 million
  • Contractor: Parsons Construction Group
  • Timeline: April 2019 - November 2020
  • Location: On US 6 (3rd Street) and Poplar in downtown Sterling

Sterling S Curve Project Locations

Crews have begun work to improve traffic flow on three highways that intersect within downtown Sterling: US Highway 6, Colorado Highway 14 and Colorado Highway 138.

Central to this project is directing large trucks driving east and west to use an "S-Curve"—a bypass using abandoned railroad rights-of way between 4th Street/Chestnut and 5th Street/Division/West Main. This S-Curve will connect CO 14 and US 6.

Specific improvements:

  • Chestnut/4th Street: A right-turn only from northbound 4th onto Chestnut, and right-turn only from westbound Chestnut/S-Curve to northbound 4th will allow crews to remove the existing traffic light. There will also be stop signs and left through movement at Poplar Street.
  • Chestnut/3rd Street: Crews will add traffic signals, two, 12-foot lanes in each direction and left-turn lanes onto Chestnut.
  • 3rd/4th Streets: Crews will convert these from one-way to two-way traffic from South Division to Broadway, with 3rd Street becoming CO 138.
  • South Division Street will be converted from a one-way to two-way street between 3rd and 4th streets, and they will reconstruct it to become US 6 north to West Main.
  • Intersection improvements will be made at 4th/Broadway and 3rd/Broadway/Sidney to accommodate the change from one-way travel to two-way roadways.
  • Crews also will reconstruct West Main Street from approximately 8th Avenue (tying into the recently completed reconstruction project) east to Division Street. Installation of raised medians, median lighting and drainage improvements—along with Americans With Disabilities Act (ADA)-compliant sidewalks and ramps—are planned with the West Main Street reconstruction.
  • Crews will repave CO 138, extending from approximately 2nd Street to just north of California Street.

Existing Conditions & S-Curve Design

The following diagrams show the existing roadway network as compared to the S-Curve design


  • Work will begin at the intersections of US 6 (3rd Street) and Poplar, and US 138 and 2nd Street.
  • Work hours: 7 a.m. - 5 p.m., Monday - Friday
  • Overnight and weekend work is not expected but may occur.

Travel Impacts

  • Expect lane closures and traffic delays in the work zone throughout the project.
  • The speed limit will be reduced to 25 mph on CO 14 and 40 mph on CO 138.
  • A width restriction of 11 feet will be in place throughout the project zone.

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