Colorado Department of Transportation and contractor Rock and Co. announced Thursday that crews have completed construction of two under-highway, downhill retaining walls, known as crib walls, on U.S. Highway 550 on Molas Pass, south of Silverton.

Portable traffic signals were removed and no delays are forecast for motorists.

The project was finished a week ahead of schedule and marks the end of three consecutive seasons of repairs to crib walls along Highway 550 between Durango and Ouray.

Nearly $7 million in construction contracts for four highway improvement projects were invested in the mountain corridor.

The reinforcement of the under-highway, slope-side walls will improve the safety and integrity of the highway.

Construction and costs of sites along Highway 550 include:

Red Mountain Pass (three projects): July 2015 to November 2015 at mile markers 88.5 to 88.6, replacement of two crib walls, excavation, culverts, retaining wall construction, minor paving, cost: $1.2 million; September 2015 to November 2015 at mile markers 89.5 to 89.7, excavation and roadway stabilization including installation of a concrete “cap” over the existing crib wall, installation of new pipe for drainage improvements and paving, cost: $1.4 million; September 2015 to August 2016 at mile markers 79.4 to 79.5, rock excavation and blasting, replacement of three crib walls below the highway, new asphalt overlay and installation of new guardrail, cost: $2.2 million.Molas Pass: May 2017 to October 2017 at mile markers 68.3 to 68.5, excavation and roadway stabilization, replacement of two crib walls below the highway, new asphalt overlay, striping and installation of a new guardrail, cost: $2 million.For more information, visit www.codot.gov.