For more than 50 years, Interstate 70 has served as Missouri's main economic artery, connecting the state's two largest cities and carrying more rural daily traffic than any other route in the state. But the decades have taken their toll on this vital corridor, with many stretches strained beyond capacity and interchange designs long outdated. Now, the Missouri Department of Transportation (MoDOT) is tackling the challenge head-on with its ambitious Improve I-70 Program, a $2.8 billion initiative to add a third lane in each direction on nearly 200 miles of highway from Blue Springs to Wentzville.
The first phase of this project falls to St. Charles, Missouri-based Millstone Weber, which broke ground in July 2024 on a 20-mile stretch between U.S. Route 63 in Columbia and Route 54 in Kingdom City. The $405 million fixed-cost design-build contract represents not just the beginning of Missouri's largest interstate construction program since the early 1960s, but also a test case for how the state will deliver the remaining phases of this massive undertaking.
"We could not be more humbled and excited," said Bob Leingang, Vice President and Chief Engineer of Millstone Weber. "This is a huge deal for everyone who drives this stretch of interstate and uses these interchanges. We will do everything in our power — and then some — to reward the confidence being shown in us to deliver this critical project."
I-70 runs across Missouri and connects three of the state's four biggest cities: Kansas City, Columbia, and St. Louis.
"It's one of our most important corridors," said Eric Kopinski, PE, Improve I-70 Program Director for MoDOT. "I-70 is one of the oldest interstates in the country, and there's been a lot of talk and planning for different improvements."
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Missouri has been studying improvements to I-70 for 20 to 30 years, but specific momentum came in 2023 when the governor and elected officials put forth funding to add a third lane across the state. MoDOT had already funded significant improvements at two interchanges through its traditional planning process — the bookends at Columbia and Kingdom City that serve as the termini for this project.
"We were just going to do those isolated interchange improvements that would do a lot of good to improve the existing bridge condition and traffic flow in those areas," Kopinski explained. "But there came a movement back in 2023 where the governor of Missouri and the elected officials put forth funding to add a third lane across the state."
The 20-mile gap between these two interchanges made it an ideal starting point.
"We had the two bookends kind of already done, and a 20-mile gap in between the two that was a little more basic than the rest of the corridor," Kopinski said. "That's why we started where we did."
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Millstone Weber teamed with Dallas, Texas-based designer Jacobs to compete against one other design-build team for the Columbia to Kingdom City project. The Missouri Highways and Transportation Commission selected Millstone Weber as the best-value proposer in February 2024, citing the team's understanding of not just the engineering challenges ahead, but also the local, statewide, and national importance of an improved I-70.
"Today's contractor selection marks the beginning of this generational opportunity to improve I-70, which serves as a critical economic east-west corridor across Missouri," said Missouri Highways and Transportation Commission Chairman Terry Ecker at the time of award. "This is a major challenge to deliver, but our MoDOT team working alongside the private sector partners in engineering and construction will deliver."
The design-build delivery method combines both design and construction phases into one contract, allowing work to progress in parallel rather than in succession. This approach saves both time and resources, critical factors for a project of this magnitude with an aggressive December 2027 completion deadline.
Missouri's fiscal year 2024 budget, signed into law by Governor Mike Parson, provided $2.8 billion in General Revenue for the costs to build a third lane across the state. This first project incorporates $123 million in previously programmed MoDOT projects to improve the I-70 interchanges at both Route 63 and Route 54.
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"The project is going to really do a lot of good for those two interchanges, but it's also going to add a third lane to eastbound and westbound I-70, and it's going to rebuild the existing pavement of I-70 in both directions," Kopinski said. "When all is said and done, we'll have 20 miles of three lanes in each direction, separated by a nice, tall concrete barrier wall that will really help with the safety that we didn't have before."
The scope includes new concrete pavement on all three lanes of I-70 in each direction for the entire 20-mile section, wider inside and outside shoulders, improved interchange designs at the U.S. 63 and U.S. 54 interchanges, two new bridges, and four new roundabouts. The commitment to maintaining traffic flow means the contractor must keep two lanes open during peak travel times in each direction, with most heavy construction work occurring overnight when traffic volumes are lower.
MoDOT's design-build approach creates opportunities for innovation that benefit both the final product and construction safety.
"We really lean on private industry from both the consultant and contracting side to bring forth innovation," Kopinski said. "That's innovation with the final improvements, with our pavement and our bridges. But specifically for the safety element, we want to make sure that at every step, both our design and what we finally implement is going to make the project safer."
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The focus on safety extends beyond the finished product to the construction phase itself.
"We want to make sure that the contracting and consultant teams are working together to design as safe of a work zone as possible, but then also really trying to limit the impact while they're constructing," Kopinski explained. "What are their work hours? When they get started, how can they more quickly or efficiently get it done, or stage the project in such a way that the safety is there?"
One of the project's most significant challenges is maintaining traffic flow on one of Missouri's busiest highways while completely rebuilding and expanding it. More than 40,000 vehicles travel this stretch of I-70 between Kansas City and St. Louis each day. The overnight construction schedule requires careful coordination and planning to maximize productivity during limited work windows while minimizing disruption to travelers.
The project leverages modern construction technology throughout.
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"Our contractor team, both on the design side, is doing everything in 3D with the plan sets. We're not really printing plan sheets," Kopinski said. "We're doing everything in a 3D model, and the contractor is running with that. So everything is stringless grading and paving."
While such technology has become somewhat common over the past decade, it represents a significant advancement over traditional construction methods.
"We're fine doing it the old school way, but we welcome this technology," Kopinski noted. "The fact we're not using stringline or doing any of that is noteworthy."
The stringless approach means operators use GPS and 3D models rather than physical string lines to guide grading and paving equipment, resulting in greater accuracy and efficiency. The technology allows for precise control of elevations and slopes, reducing rework and improving the quality of the finished pavement.
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For traffic modeling and planning, MoDOT uses advanced software to ensure the improved interchanges will function efficiently both at opening and 20 years down the road.
Just over a year into construction, Millstone Weber has already achieved a significant milestone. In November 2025, the team completed the first 7 miles of new pavement on eastbound I-70 between Route J (mile marker 137) and Route M (mile marker 144). Brandy Broeckling with Millstone Weber noted that barriers were removed from the completed stretch by the end of that week, allowing traffic to experience the improved roadway.
"We are standing on brand new pavement, a little over a year from when we broke ground up at the Drury Inn. And that is just incredible progress," said MoDOT Director Ed Hassinger at a ribbon-cutting ceremony celebrating the completed section.
The project remains on schedule and on budget.
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"We awarded this project back in 2024 and the completion deadline is December of 2027, so we're kind of in the thick of it," Kopinski said. "We're on schedule and on budget, and everything's moving along as expected, which is a good thing given how significant this project is — both regionally, but then also just dollar-wise. It's one of the biggest projects we've delivered in our state."
The early completion of the first 7-mile section demonstrates the efficiency of the design-build approach and the contractor's ability to deliver quality work on an aggressive timeline. The completed pavement provides motorists with a preview of what the entire 20-mile corridor will look like upon completion in 2027.
Beyond adding the third lane, the project includes substantial improvements to two major interchanges. The I-70/U.S. 63 interchange in Columbia and the I-70/U.S. 54 interchange in Kingdom City both receive complete redesigns to improve traffic flow and freight movement. MoDOT uses advanced traffic modeling to ensure these interchanges will serve the region well into the future.
The U.S. 54 improvements include two new bridges, while the overall project features four new roundabouts designed to improve traffic circulation and reduce conflict points. These modern interchange designs will better accommodate the increased traffic volumes and provide safer, more efficient connections between I-70 and the intersecting routes.
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The interchange work represents some of the most complex construction on the project, requiring careful phasing to maintain access for local traffic while reconstructing ramps, bridges, and approaches. Work on the U.S. 63 interchange began in 2024, while construction on the U.S. 54 interchange started in 2025.
The Columbia to Kingdom City project serves as more than just the first phase of I-70 improvements. It represents a potential blueprint for how states can efficiently tackle aging interstate infrastructure nationwide.
"The interstate system is becoming outdated and in need of significant investment, significant repair," Kopinski said. "Everybody's looking at each other asking, 'How do we go about rebuilding this or doing significant work?' I think we in Missouri would say our I-70 statewide program is a good way to quickly rebuild the interstate system, efficiently, on time, and on budget."
Other states have taken notice.
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"Some others have come and talked with us to see how they can quickly make significant progress on their aging infrastructure," Kopinski noted. "We kind of see this as a potential national model. I know every state's a little different, but we tend to view that as a good best practice."
The design-build approach, combined with Missouri's commitment to funding the entire program upfront, allows for economies of scale and continuity that would not be possible with traditional project-by-project funding and delivery. The model could be particularly attractive for other states facing similar challenges with aging interstate corridors.
The Columbia to Kingdom City project is financed through Missouri's General Revenue fund, part of the state's $2.8 billion allocation for the entire Improve I-70 Program. The fixed-cost design-build contract provides budget certainty for MoDOT while incentivizing the contractor to control costs and maintain efficiency.
Subsequent phases of the broader program include improving stretches from Warrenton to Wentzville and from Blue Springs to Odessa, with the entire 200-mile program expected to be completed by 2030. The statewide program represents one of the largest state-funded infrastructure investments in Missouri history.
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The expansion to three lanes in each direction will provide critical benefits beyond just increased capacity. Emergency vehicles will be able to access crashes faster with less traffic backup, improving safety and reducing congestion. The modernized interchanges will better accommodate freight movement, supporting Missouri's role as a logistics hub.
"I-70 is one of Missouri's oldest and most vital corridors," Parson said at the project groundbreaking. "The safety and economic prosperity of Missourians depend on an interstate that grows along with the state and nation. Expanding I-70 to six lanes has been talked about in Jefferson City for decades, but our administration — in working with Senator Lincoln Hough and the General Assembly — is taking action."
For Millstone Weber, the project represents a significant undertaking and an opportunity to demonstrate its capabilities on a project of statewide importance. The full-service heavy civil construction company has experience across the transportation industry, including rail and transit, highway, bridge, and aviation sectors. The firm is currently building the I-270 North project in North St. Louis County, Missouri, and has worked on projects including the Denver International Airport Concourse Expansion.
As work continues through 2027, drivers on this stretch of I-70 will watch Missouri's transportation infrastructure enter a new era. The project will deliver safer, more efficient travel for the more than 40,000 vehicles that use this corridor daily, while serving as a model for how states can successfully tackle the challenge of rebuilding America's aging interstate system.
