On May 7, 2026, the flyover ramp from northbound U.S. 75 to eastbound Interstate 44 in Tulsa, Okla., opened to traffic.

That's two open, two more to go.

The first of the $252 million project's four ramps opened in April 2026. The project to reconfigure the interchange is moving steadily toward its expected summer 2028 completion date, according to the Oklahoma Department of Transportation (ODOT).

Drivers along the U.S. 75 and I-44 corridors will finally be free of the 1960s-era cloverleaf interchange and the dangerous lane-merging derby at its tight entrances and exits that can no longer safely accommodate the growing volume of traffic.

Cloverleafs, built for light, rural traffic, have been called "congestion machines" in places where urban growth has taken over. The U.S. 75 and I-44 interchange is a prime example.

Construction has gone smoothly, Trapper Parks, ODOT's engineer for District 8, which includes Tulsa, told Construction Equipment Guide. If there was any surprise, it was that Tulsans adopted the bridge piers built in an earlier phase of the project as a steel-and-concrete mascot.

To drivers and the city's traffic reporters, those empty piers looked a lot like Great Britain's Stonehenge.

Three Projects in One

That earlier phase wrapped up in 2023 at a cost of $90 million. Sherwood Construction of Tulsa was the prime contractor.

The current construction, which began in April 2025, is led by Tulsa-based Manhattan Road and Bridge. The work combines three projects into one, Parks said.

"We had the luxury of packaging three of these projects together because of some federal grants that we received that allowed us to expedite some of the construction," he said. "So, it'll all be done from a public perspective as one seemingly seamless project, but it is three individual projects that are being constructed at once."

At $252 million, the three projects together are "Oklahoma's largest single investment in transportation infrastructure ever," ODOT Executive Director Tim Gatz said.

That took careful planning on the design front.

"You've got three different projects that have to marry together perfectly," Parks said. "And so, you've got a lot of collaboration and coordination between design teams. It wasn't all the same designer doing all three projects."

Benham Design is working on two of the packages, and Poe & Associates is working on a third.

Such collaboration is common, Parks said, "but probably not to this extent, to where you've got multiple bridges at multiple levels tying into roadways and ramps.

"And many of the piers were built in the first phase of the project. And so, you've got to have a lot of confidence in where those piers are in the plans, because you're relying on those for a future project to come behind you and put beams on those piers."

More than 20 construction crews are at work on the project, according to ODOT. They're operating eight cranes, three dozers, seven forklifts, six manlifts, 10 loaders and a paving machine.

"The biggest crane that they've had on site was a 900-ton crane — LTM 1750 was the model," Parks said, adding, "12 cranes on site at once is not normal for one of our projects."

Under the wheels of passing vehicles will be about 15,200 cu. yds. of Class AA concrete and 7,130 cu. yd. of Class A concrete, T.J. Gerlach, an ODOT public information officer, told Construction Equipment Guide. Construction materials also include 6.5 million lbs. of reinforcing steel and 9.6 million lbs. of structural steel.

"Bridges are typically the most expensive component of our projects," Parks added. "In this project, our longest flyover bridge is about 2,400 feet long. And one of the complexities is that it's on a curve. You're over live traffic. It's going over two major highways and it's way up in the air" — about 80 feet.

"And so just the construction sequencing to determine where we place our cranes in order to pick up these beams and get them into place safely — How do we handle traffic while that's happening?

"But also the components of a bridge are expensive. The longest bridge is roughly $25 million. From a unit cost perspective, that's way up there."

Steel components, concrete deck and labor: "They add up quickly on a bridge project," Parks said.

‘Henge-ing' Their Bets

Two years separated the completion of the first phase and the beginning of the remaining phases in 2025. In the interim, drivers drove by the incomplete piers dotting the interchange. To some they looked like goal posts. To others they looked like a modern steel Stonehenge.

Parks said ODOT first noticed people talking on social media about "Traffic Henge" and "Road Henge" and "Tulsa Stonehenge." Traffic reporters picked up the chatter.

Now those "henges" are steadily disappearing under the bridges they were built to support.

ODOT got a lot of ribbing about the piers that carried no bridges. But, Parks said, "It made a lot of sense to build the piers on that [first] project because we were able to minimize traffic impacts and not do rework. We were already doing work in that same exact footprint. So, while we were there, we went ahead and built a lot of those piers just from an efficiency standpoint.

"People don't always understand exactly why we're doing what we're doing, but there was method to the madness," he said.

When completed, what will all the work at the U.S. 75 and I-44 interchange have accomplished?

There will be "a much safer facility, a much more efficient facility. People will get through there quicker, won't have to wait in traffic," Parks said, adding,

"It got to a point to where our traffic grew and that cloverleaf design broke down from an efficiency standpoint. You have multiple people trying to get in the same place at the same time. That results in elevated congestion but also in additional crashes.

"So, there'll be a lot of improvements for quality of life of the people in the area."

Additional Improvements

Work around the U.S. 75 and I-44 Interchange includes:

• widening U.S. 75 between 71st Street and 41st Street;

• replacing the U.S. 75 interchange at 61st Street;

• building a new frontage road between 61st Street and Skelly Drive;

• extending and connecting 51st Street under U.S. 75; and

• constructing a pedestrian bridge over railroad tracks along 51st Street near Elwood Avenue.