Turner Diagonal Interchange Redesign Transforms I-70

By Chris Roberts and Justin Adams, Contributing Authors 

The situation: An outdated connector at a crossroads.

In Kansas City, Kan., Interstate-70’s Turner Diagonal Interchange was a critical freight and commuter corridor linking neighborhoods, industries and highways for decades. But its outdated design — a tangled mess of short loop ramps and awkward mergers, originally intended to support a toll plaza that never materialized — had become a bottleneck for commerce and a risk for commuters. 

It was a barrier to future development, ill-equipped to keep pace with a region experiencing significant growth.

The challenge: tight constraints, high stakes.

The I-70 interchange handled more than 65,000 vehicles a day—25% of them trucks—and demanded more than repair. It required a complete reinvention.

Reimagining the Turner Diagonal, the project’s team grappled with tight right-of-way limits, aging infrastructure and complex coordination across a public-private alliance. 

Project partners included the Kansas Turnpike Authority (KTA), Kansas Department of Transportation (KDOT), the Unified Government of Wyandotte County and Kansas City, Kan., and NorthPoint Development.

Then COVID-19 hit. The team received their notice to proceed in January 2020, weeks before the pandemic slowed down the world. Virtual stakeholder meetings, redesigned job site protocols and agile scheduling adaptations became the norm. However, momentum never stalled.

“There were a lot of moving parts — tight right-of-way, aging infrastructure, and a real need to keep trucks moving through it all,” said Jason Van Nice, bureau chief, construction and materials at KDOT. “This wasn’t a flashy project, but it mattered. It’s the kind of fix that clears the way for everything else to work better.”

The solution: A smarter interchange for a stronger region.

Led by GFT on design and Clarkson Construction on delivery, a diverging diamond interchange (DDI) was chosen to solve the capacity and safety challenges while also reducing the interchange footprint. 

The DDI allowed for smoother left turns, fewer conflict points and more efficient truck flow — all within the bounds of existing infrastructure.

The team minimized demolition and accelerated delivery by carefully reconfiguring the layout and preserving two key bridges. This also unlocked more than 300 acres of land for commercial development.

Project Schedule and Funding

The Turner Diagonal Interchange project followed a highly accelerated timeline due to its design-build delivery approach. Key milestones included:

•    RFP release: Sept. 9, 2019.
•    Design-build contract awarded: Nov. 1, 2019.
•    Notice to proceed: January 2020.
•    Interchange open to traffic: Sept. 7, 2020.
•    Construction completion: Nov. 30, 2020.

Despite the onset of the pandemic, the project adjusted to virtual communication and jobsite protocols. Critical operations, such as the 37-day full closure of the Turner Diagonal and associated ramps, allowed for around-the-clock construction with no recorded safety incidents.

The team completed four phased design packages in under five months, including bridge rehabilitation, ramp demolition, retaining wall construction, new pavement and installation of advanced traffic monitoring systems.

The total construction cost for the Turner Diagonal Interchange project was $30.3 million, and the project was delivered on budget.Funding sources included:

•    INFRA Grant (Federal): $13,843,600 (46% of total costs).
•    Local & State Contributions (Unified Government, KDOT, KTA): $15 million.
•    Private Investment (NorthPoint Development): $1.5 million.

This blend of federal, state, local and private investment reflects the collaborative commitment to improving regional freight mobility and stimulating economic development. 

This also unlocked more than 300 acres of land for commercial development—a major win for economic growth in the region. Five new warehouse facilities have been opened in the vicinity following the completion of the project.

“This interchange serves as a vital gateway for freight and local traffic. From the KTA’s perspective, the goal was maximizing mobility and safety for all users,” said David Jacobson, chief engineer at KTA. “The collaborative approach allowed us to tackle longstanding inefficiencies and deliver a project that will serve Kansas for decades.”

Construction Innovation

The Turner Diagonal interchange project was completed as a design-build delivery, with the KTA overseeing the processes. 

The design was split into four phased packages to allow early construction starts. A strategically planned 37-day full interchange closure allowed work on critical paving and ramp work seven days a week, with zero safety incidents during that window.

Geotechnical issues pushed the team to think creatively. Ramps requiring up to 35 feet of fill demanded settlement monitoring, geopiers and lightweight materials to manage load stress and protect existing utilities. 

Truck parking, staging and inspection lots to the west of Turner Diagonal were completely redesigned with a new inspection building, improved site circulation and new technology. This included a Truck Parking Information Management System (TPIMS) that provides real-time parking availability to drivers via dynamic truck parking signs installed along I-70. 

Community Access and Connectivity

Beyond freight mobility, the project improved community accessibility. More than two miles of ADA-compliant sidewalks and shared-use paths were added, including a new pedestrian crossing over I-70, where none existed.

Transit enhancements connected underserved neighborhoods to RideKC’s Route 106, while sidewalk lighting and pedestrian safety features brought new levels of accessibility and opportunity to the corridor.

What began as a highway redesign ultimately became a bridge to jobs, mobility and economic inclusion.

Results

Conflict points were reduced from 26 to 14, which means safer mergers.

Improved freight efficiency comes in the form of faster staging, reduced drayage times and improved triple-trailer access.

There promises to be economic development with 300 acres unlocked for commercial and industrial development, as well as regional freight improvements and reduced emissions from decreased idling and optimized signals.

Looking Ahead

The Turner Diagonal Interchange represents more than a transportation upgrade. It demonstrates how strong public-private collaboration can lead to safer roads, better freight networks, and inclusive community infrastructure.

As freight traffic in Kansas trends towards $400 billion annually, this project exemplifies what modern infrastructure must be: connected, collaborative and built for everyone.

Justin Adams, P.E., is a project manager and senior highway engineer with GFT in Kansas City, Mo.

Chris Roberts, P.E., is a traffic engineer with GFT who has specialized in traffic design and safety improvement studies in the Midwest over the past decade.