Motorists traveling along Interstate 70 will soon see the first signs of construction for the massive, $1.2 billion plan to make over a 10-mile portion of the highway through north Denver.

The official groundbreaking happened around 8:30 Friday morning. Crews will now begin work on nearby side streets, such as getting utilities out of the way and doing surveying work, said Rebecca White, a communications manager for the Colorado Department of Transportation (CDOT).

"Starting here pretty quickly, drivers out there will start to see some...cone zones," White said.

White added that during daytime hours, three lanes will be kept open, the "same as we have today."

"We’ve told the contractor they can only drop lanes or close lanes overnight," she said.

The first major closure related to the project will start in about a month, White said, along East 46th Avenue between York Street and Brighton Boulevard.

Project overview

The "Central 70" plan includes ripping out the crumbling I-70 viaduct across north Denver, expanding the highway between Interstate 25 and Chambers Road using toll lanes and sinking a portion of the highway between Brighton and Colorado boulevards.

A 4-acre park will be built across the highway between Columbine and Clayton streets.

CDOT said the purpose of the project is to alleviate traffic congestion in the area and ensure the integrity of the highway's 54-year-old viaducts by providing the "first safety and capacity improvements ... since the highway's construction in 1964."

The project will also enhance pedestrian and bicycle connectivity by incorporating 8-foot sidewalks, tree lawns and lighting along roads, CDOT said.

Who's building it?

The project is a public-private partnership between the Colorado Department of Transportation (CDOT) and Kiewit Meridiam Partners.

Kiewit is a large North American transportation contractor that has worked on other Colorado projects, to include T-REX, the Interstate 225 light rail line and Denver Union Station transit improvements. Meridiam is a global investor and asset manager specializing in infrastructure projects.

Several other companies are also part of the partnership. CDOT also said it will create 4,000 to 5,000 new jobs and that 20 percent of the jobs will go to people who live in nearby communities.

How long until it's complete?

According to CDOT, the project will take four years, with an estimated 2022 completion date.

Embroiled in controversy

Controversy surrounding the project focused on what might happen to homes and residents in the nearby Globeville and Elyria-Swansea neighborhoods.

One suit, filed in March 2016, argued that the Environmental Protection Agency violated the Clean Air Act after it changed emission standards, allowing the project to go on.

Then, attorneys for environmental and community groups said in a November 2016 complaint that the project would negatively impact the community, which is made up of predominantly Latino residents.

But the Federal Highway Administration in April 2017 released a report that found that although the project is not without issues, it is the best option compared to others studied.

Yet another suit, filed in July 2017, argued that impacts to health and environment were not fully studied.

None have succeeded in halting the project. CDOT acquired 56 homes (all in Elyria-Swansea) and 17 businesses to make way for the project and also committed $2 million in affordable housing funding to the neighborhoods.

Click/tap here for more information on the Central 70 project.