Drivers could experience delays through sections of Interstate 70 during the next year as construction crews replace an emergency access structure that runs beneath the interstate near Eisenhower-Johnson Memorial Tunnel, the Colorado Department of Transportation announced Thursday.

The replacement of the emergency access structure is necessary to protect the structural integrity of the road which emergency vehicles, including law enforcement and ambulances, use to navigate busy portions of the interstate between the Eisenhower-Johnson Memorial Tunnel and Silverthorne, the department said.

The structure is a single-lane concrete box culvert built during the tunnel’s original construction in the 1960s. Over the course of many decades the structure has deteriorated and requires “immediate replacement,” the agency said. 

Starting mid-week westbound drivers will see traffic reduced to two lanes from the tunnel until mile post 211. The project will pause during the winter months of heavy ski traffic, with all six lanes of traffic open. The construction is set to be completed in spring 2022, the department said.

When finished the emergency structure will be wider and able to serve two way traffic, the agency said.