/ Articles / Engineering A More Just Tomorrow: P3 Contracting and Construction Innovation Combine to Catalyze Central 70

Engineering A More Just Tomorrow: P3 Contracting and Construction Innovation Combine to Catalyze Central 70

Sean O'Keefe on May 10, 2023 - in Articles, Feature, Featured

A more just tomorrow starts with equitable access to life’s simplest treasures, and a good day at the park certainly qualifies. CDOT’s Central 70 project replaces an intrusive infrastructure with a crown jewel that reconnects life-long neighbors, families and friends in north Denver.

In 1956, President Dwight D. Eisenhower signed the Federal-Aid Highway Act to launch what was at the time the largest public-works project in American history. With an original authorization of $25 billion earmarked to build some 41,000 miles of the Interstate Highway System during a 10-year period, the bill also was known as the National Interstate and Defense Highways Act because the Interstate alignments strategically connected U.S. military bases of various sorts across the country.

That is history as projected. History, as realized, however, reveals other less-pragmatic thinking on exactly where Interstate highways ought to be built as they connected the country’s large, already substantially populated, urban centers.

In Denver, as in other cities across the country, the original planners chose to place the new highway’s massive alignment through areas that were considered “blighted” in hopes of revitalizing underperforming parts of the city. Although the intent may have been expressed as noble at the time, in 2023, after more than 70 years, it’s difficult to argue that the consequences of those choices haven’t been devastating for the affected communities.

Learn from Mistakes

Today, infrastructure remains an opportunity to improve upon what has been done before. Perhaps in our time, the infrastructure we build can help heal past wounds in hopes of a more just tomorrow.

“Back in the late 1950s, when the alignment for I-70 through Denver was determined, the environmental process was non-existent,” says Bob Hays, project director for the recently completed Colorado Department of Transportation (CDOT) Central 70 project.

Stretching 10 miles along Denver’s industrial corridor, Central 70 adds Express Lanes in both directions to increase driver choice and alleviate congestion during peak hours. Completed through a P3 with Kiewit Meridiam Partners LLC, the contract allows CDOT to pay for the work through monthly availability payments.



Hays has been with CDOT for more than 20 years, a tenure that included overseeing a series of innovative infrastructure improvements intended to enhance the state’s transportation network by leveraging public-private partnerships (P3s). He takes special pride in CDOT’s latest effort, Central 70, which in addition to replacing and rehabilitating severely aged infrastructure also reconnected long-severed populations of black, brown and immigrant communities along Denver’s industrial edge.

“Sadly, the alignment was poorly chosen,” notes Hays, who has been involved in rethinking Central 70 since 2015. “From Brighton Boulevard to Colorado Boulevard, I-70 was built on a viaduct, 25 feet in the air, which cut a swath through several North Denver communities. This divided families, friends and neighbors, and caused a lot of scars. The Central 70 project was a wonderful opportunity to attempt to right some of those wrongs.

“Starting in about 2000, CDOT was dealing with a 40-year-old viaduct bridge that was starting to fall apart and began considering alternatives,” he adds. “Through a 15-year process, CDOT ultimately came to a Record of Decision to go with the Partially Covered Lowered option (PCL).”

Kiewit’s top-down construction methodology involved excavating and building foundation caisson walls as they went. Here, one of the massive girders used to construct the park lid above the lowered section of I-70 is being put in place by crane.


In lowering the alignment from overhead to below grade, Central 70 reintroduced cross-community connections at-grade and built more than 2,000 linear feet of new sidewalk to enhance pedestrian and personal mobility opportunities.


The Central 70 Project reconstructs a 10-mile stretch of I-70 along the northern fringe of Denver between Chambers Road and Brighton Boulevard, while adding a new Express Lane in each direction as well as several over changes and bridges. Undertaken as a P3 program with private-sector partner Kiewit Meridiam Partners LLC, the $1.2 billion project also is noteworthy for pursuing a design-build-finance-operate-maintain (DBFOM) delivery model that allowed CDOT to actualize its gargantuan task. Among accomplishments, however, the crowning achievement is a community jewel that will change lives in many ways.

“The PCL called for tearing down the viaduct and shifting the alignment slightly north so it could be lowered,” says Hays in revealing the big win. “The key feature of the Central 70 project is a new 4-acre park placed on top of the lowered Interstate that reconnects this community at grade.”

Nothing about this sounds simple, and it wasn’t. Among the many possible hurdles, Hays shares that re-engaging with this community and earning its trust was a massive and intentional undertaking. He and the team at CDOT held more than 300 public meetings during the project. Hundreds of those meetings focused on public input as to what the park needed, and what it should look like—even colors and material choices were considered. The level of public engagement and opportunity for comment was the highest in CDOT’s history, and Hays is proud that it wasn’t just to get people’s opinions.

“Perhaps there were some who wanted this segment of the alignment removed altogether, but we also must appreciate that this piece of highway moves hundreds of thousands of cars every day. So we can’t just take it away. It’s a delicate balance,” he shares of CDOT’s genuine ambition to serve the greatest good. “We tried to meet people where they are. We engaged them in solution-based conversations around connectivity and multi-modal transportation. Among many betterments, we built more than 2,000 linear feet of sidewalks and made them 8 feet wide so bikes, pedestrians and personal mobility can all coexist.”

Community Investment

While the park-covered lid over the highway and much-enhanced community connectivity were big-picture engineering objectives, CDOT’s direct investment in the lives of those impacted by construction is what makes Central 70 an exemplar for the future of smart city building. As part of the federally approved Record of Decision, CDOT agreed to deliver nearly 150 community commitments as part of Central 70. Noteworthy among them is a substantial investment in the future.

“Beyond the outreach, CDOT engaged an unprecedented number of mitigations to improve people’s lives,” he continues. “We invested about $19 million in Swansea Elementary School, which resulted in two new classrooms, HVAC upgrades and a new playground. The school connects directly to the park over the highway, and the principal shared that this year, for the first time, the students will have a field day.”

CDOT’s long list of community commitments also includes investments in the individual lives impacted by four years of construction. CDOT mandated a 20 percent local hiring requirement based on a geographic radius and launched a workforce development program as well as a neighborhood training center to stimulate a community-based workforce.

The project’s Home Improvements program provided interior storm windows and air-conditioning units as well as financial assistance for utility costs to residents between 45th and 47th avenues and Brighton to Colorado Boulevard to help mitigate dust and noise during construction. Central 70 funded improvements to more than 260 homes by the end of 2018 when construction began. CDOT also awarded a $2 million grant to the Globeville, Elyria-Swansea Affordable Housing Collaborative to support affordable housing development in the Elyria and Swansea neighborhoods.


A stunning transformation that almost disappears. There could perhaps be no better measure of success in infrastructure than for it to be unintrusive.


Beneficial Partnerships

“Fundamentally, CDOT could not take on a project of this magnitude without partnerships. Here that included partnerships with the community, the City and County of Denver, and the incredible P3 team put forth by Kiewit Meridiam Partners,” continues Hays, whose previous experience included developing the U.S. 36 design-build P3 project to add express lanes between Denver and Boulder. There the scope of work involved adding high-occupancy toll lanes in each direction along a 16-mile corridor between the two cities.

“On U.S. 36, a toll collected from vehicles using the express lane goes to investors that own, operate and maintain the asset under a 50-year agreement,” he says. “On Central 70, the DBFOM P3 agreement allows CDOT to own and maintain the assets. We are paying for this by making monthly availability payments to the developer—like a mortgage.”

More than simply providing a mechanism by which CDOT could afford to accomplish such a massive scope of work, the P3 process also is essential to manage risk.

“P3 contracting allows a public-sector entity like CDOT to shift the burden of risk on a project like this from the taxpayer to private industry,” says Hays of an infrastructure-building “lubricant” that is difficult to quantify. “Whether it happens to be hazardous materials, utility issues or severe weather delays, the Kiewit Meridiam team is far-more adept at solving those problems through the incredible expertise, know-how and horsepower they can apply when needed.”

Central 70’s Key Wins in Smart City Building

Safety: Wider shoulders on both sides of travel make vehicle pull-off and emergency response safer while improving highway drainage.

Economic Vitality: Improved surface road design makes local access safer and more efficient, which translates up economically.

Driver Choice: With the addition of Express Lanes, I-70 drivers can use free general-purpose lanes or pay a toll in exchange for a reliable travel time.

Local Connectivity: North, south, east or west, residents of the Elyria-Swansea neighborhoods now can get there by foot, bike, scooter, car, bus or whatever comes next. Or they can meet at the park right in the middle.

Equitable Mobility: CDOT’s balanced approach to mobility facilitates system reliability on the Interstate with a significantly enhanced local roadway network that accommodates personal mobility and public safety at the neighborhood scale.

Future Capacity: Central 70 accounts for realistic capacity expansion by preserving right-of-way that ensures the efficient movement of people and goods without further public disruption.

Complicated Engineering

In terms of potential challenges, Central 70’s scope of work entailed reconstructing an active highway during weekday traffic through the central artery serving a local population of 1 million. With daily traffic on the viaduct above, the new alignment placed half of the lowered section north of the viaduct.

“As they excavated down to the final depth, Kiewit built foundation caisson walls to support the excavated earth. From an engineering standpoint, it’s hard not to be impressed with this top-down construction trenching methodology,” says Hays. “Then the cap over the top is essentially a massive bridge. So that meant traditional bridge-building methodologies—with abutments and pier caps and an astounding number of girders side-by-side—to create a 1,000-foot tunnel.”

Among less overt successes, Hays reveals that the Central 70 project also helped CDOT rethink its approach to coordination with the massive project’s many stakeholders—most prominently the City and County of Denver and local utilities.


Among almost 150 community commitments CDOT made as part of the Record of Decision, some $19 million was invested in Swansea Elementary School. The 2023 school year will conclude with the school’s first-ever field day while thousands of vehicles pass beneath.


“When Kiewit took on this project, they found Central 70 had more utilities per acre than any project they had ever built. This team took a very strategic approach to relocate those utilities out of the corridor,” says Hays of a whole suite of essential services clogging up the work zone. “Much of that has been attached to the bridges and crossings we built, where it’s hidden but still accessible to owners. Central 70 was completed without a single claim or issue associated with utilities, whereas much smaller projects have incurred huge issues. To build something like this, you can’t do it alone.”

Hays applauds the City and County of Denver for committing a full-time staff of four to Central 70, which allowed CDOT to move expeditiously through the City’s permitting processes. That was critical because Central 70 was not the only high-impact civic improvement happening in this long-neglected section of the city. At the western end of the work zone, the National Western Stock Show is undergoing a much-needed revitalization of its own. Likewise, the City and County of Denver completed a drainage-improvement project parallel to the new alignment during Central 70’s construction.

“The teamwork between this project’s many partners was the gold standard,” says Hays confidently. The proof is in the pudding. “For all this work to be done and operational without any claims, disputes or detrimental impact on daily commutes for four years is pretty remarkable. P3 is not for the faint of heart, but with a project-first mentality you can do some amazing things.” 


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About Sean O'Keefe

Sean O'Keefe is an architecture and construction writer who crafts stories and content based on 20 years of experience and a keen interest in the people who make projects happen; email: [email protected].

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