CDOT begins $806 million project on busy Denver freeway

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(The Center Square) - A major Denver freeway is undergoing an extensive repair project that costs taxpayers $806 million.

The Colorado Department of Transportation has begun work on Interstate 270, with construction expected to finish in 2033 on the busy 61-year-old freeway. But critics doubt whether the project will resolve congestion, and they're raising concerns about the project leading to more traffic and a bigger environmental impact.

The project will replace 12 bridges, add a tolled express lane in each direction, improve highway onramps, widen I-270 and its shoulders, and add a continuous auxiliary lane, according to CDOT.

The project is divided into three phases. The first phase will focus on bridge repair and limited design and reconstruction of I-270, costing $307 million, according to CDOT.

This phase is expected to be completed by early 2030, CDOT said.

Phase two will focus on finishing the remaining parts of I-270, costing $402 million.

The third phase will complete the design and construction of pedestrian overpasses and fund community enhancement efforts, costing $97 million.

CDOT noted that these phases are expected to start in early 2030 and finish in 2033.

Stacia Sellers, CDOT's major projects and operations communications manager, told The Center Square that the transportation project's goal is to improve infrastructure built in 1965.

Sellers described I-270, which carries over 100,000 travelers daily, as a “critical economic corridor” where people commute to Boulder, Aurora and Commerce City, all within an hour of Denver.

The express lane will make travel times more reliable and meet “the purpose and need of the corridor and address some issues that commuters have been facing," Sellers said.

The express lane will keep traffic moving instead of having traffic “come to a standstill,” she explained.

But Alex Schluntz, a senior attorney at the environmental legal nonprofit Earthjustice, said the transportation project won't “solve congestion.”

According to Schluntz, Earthjustice hired an independent modeler to review CDOT’s proposal and found it will “move congestion around in the system, and it will result in longer commute times for many residents in Commerce City,” which is home to nearly 75,000 people.

Schluntz said tolling existing lanes would address congestion concerns and “meet the needs of users, including freight traffic, because it actually accounts for and understands how building [Colorado’s] transportation system interacts with demand.”

Adding tolls “uses travel demand management policies to reduce congestion,” she explained.

Tolls also make sure the “corridor is available for local users and freight traffic,” Schluntz said.

Regarding tolling existing lanes, CDOT ran the project through its traffic model and “determined it did not meet the project’s purpose and need,” Sellers noted.

As part of the transportation project process, CDOT worked with environmental groups, Sellers said.

She noted the department is “adding in air quality monitors along the project.” CDOT will also add “greener streets” and plant more trees between neighborhoods and local industry in areas affected by the construction project, Sellers said.  

CDOT is also considering carpooling incentives, microtransit and implementing more bus stops in the project's impact areas to “get more vehicles off the roadway,” Sellers explained.

Despite these efforts, Schluntz said the project will “increase pollution levels.”

CDOT is “underestimating the air quality impacts and greenhouse gas emissions” that will come from the project, she noted.

To help reduce pollution, Schluntz recommended that CDOT use “zero-emission equipment wherever is suitable” and fund more regional transit options.

Schluntz said Earthjustice is “still evaluating all options to continue addressing the harms from the project and to protect the community.”

A significant portion of the I-270 construction will occur in Adams County, the state's fifth-most populous county, home to nearly 550,000 residents.

Adams County Board of Commissioners Chair Julie Duran Mullica said the success of the project should be measured “by the benefits to surrounding communities, including improved pedestrian and bicycle connections, additional transit options and the community enhancements incorporated into the project.”

“For Adams County, this is about making an important regional corridor safer and more reliable while also improving connections and transportation options for our residents,” she told The Center Square by email.

Mullica noted that some of the county’s top priorities during the construction project include “protecting local streets from unnecessary freight traffic and maintaining access to neighborhoods and businesses.”

CDOT has been working with “local businesses to understand freight movements and identify ways to minimize disruptions,” Mullica explained.

Adams County expects the “project to improve transportation reliability, strengthen connections between major regional highways and support continued economic activity," Mullica said. 

She noted improving I-270 is an “important investment in the long-term economic vitality” of the county’s community.