Missouri DOT’s $246M Corridor Transformation Targets Safer, More Reliable Travel
Date Posted: July 7, 2026
Posted In: News, Projects,
From Construction Digest: Overcoming significant logistical and coordination challenges, a design-build team is making steady progress on a $246 million corridor improvement project along Interstate 55 in Jefferson County, Missouri. Led by KCI Construction of St. Louis in partnership with the Missouri Department of Transportation (MoDOT), the effort is focused on expanding capacity, improving safety, and supporting continued growth in one of the region’s busiest commuter corridors. Bartlett & West of Topeka, Kansas, with offices in St. Louis, serves as the lead design partner on the team.
The project is designed to eliminate long-standing bottlenecks, modernize more than 20 structures, and introduce a new grade-separated interchange. While much of the work remains ongoing, the complexity of the job — from maintaining traffic to coordinating with railroads and utilities — has required a high level of planning and adaptability from both the contractor and owner.
Transforming a Critical Corridor
The I-55 corridor project extends from Pevely to Festus, Missouri, and centers on the addition of a third lane in each direction. In addition to widening the roadway, the project includes replacing or rehabilitating more than 20 bridges; constructing a new interchange at Route 67 and Route CC, including roundabout construction at the I-55/Highway 67 intersection; installing sound walls; and upgrading pavement throughout the corridor.
“KCI is contracted to design and build a third lane of I-55 from Pevely to Festus, Missouri,” said Brian Mulhall, Vice President of Transportation at KCI Construction. “There are various other improvements with the project, including updating or replacing over 20 structures throughout the corridor.”
The work is being delivered through a design-build model, allowing design and construction teams to collaborate closely and respond quickly to changing field conditions. That flexibility has proven valuable, given the number of moving parts involved.
The need for these upgrades stems from a long-standing reduction in lane capacity that created daily congestion and safety concerns.
“Basically, Interstate 55 went from six lanes, down to two lanes each direction with a grass median,” said Justin A. Wolf, I-55 Jefferson County Project Director for MoDOT in the St. Louis District.
“That was a daily bottleneck for traffic. It would hit that point where it drops to two lanes, and they’d back up, and there’d be crashes there,” Wolf added.
Traffic flow was further restricted at the southern end of the corridor, where a signalized intersection created additional delays.