A major closure along Interstate 70 began overnight in Denver as roadwork to make preparations for the ‘Mile High Shift’ began.

Both directions of the interstate from Washington Street to Interstate 270 will remain closed until 5 a.m. Monday, and currently everything is on schedule, said Stacia Sellers, a spokesperson for The Colorado Department of Transportation.

“Everything is going really well so far today,” Sellers said in an email statement to The Denver Gazette.

Crews will be safely demolishing and moving all six lanes of I-70 between Brighton and Colorado Boulevards from the existing viaduct to the future westbound lanes of the interstate in a lowered section of CDOT’s Central 70 project.

Additionally, crews will bring down the current 57-year-old viaduct and build out into the future eastbound lanes of the interstate.

Crews spent the day demolishing the old lanes of the interstate, Sellers said.

Despite the closures, traffic for the most part flowed along the detours across town, Sellers said.

This weekend’s roadwork marks a major milestone for CDOT’s $1.2 billion project that broke ground in 2018. The project will reconstruct a 10-mile stretch of the interstate, while also adding a new Express lane in both directions.

“CDOT has been looking forward to the Mile High Shift since we broke ground in August 2018 and are proud of everything our crews have accomplished in order to get here,” Sellers said.

CDOT anticipates traffic modifications will reach its final stages by late 2022, but landscaping, installation of park elements and additional work will continue through 2023.