Construction began Monday on the I-44 and U.S. 75 interchange in Tulsa, Oklahoma, known to locals as "Tulsa’s Stonehenge" and "Traffic Henge" due to the towering empty bridge piers left standing for years, Oklahoma DOT said in a news release. The state has identified it as one of the most outdated, unsafe and congested areas of Tulsa’s I-44 Corridor.

The $252 million project aims to revamp the interchange and other infrastructure in the area. It combines three phases into one and represents the most expensive contract the Oklahoma DOT has ever undertaken, according to the release. The agency tapped Tulsa-based Manhattan Road & Bridge for construction. 

Piers for future flyover ramps were built in advance during the $90 million Phase 1 in 2023 in order to save time and reduce traffic disruptions once funding became available for the remaining phases, the agency said.

The main part of the project entails completing the reconfiguration of the I-44 and U.S. 75 interchange, according to Oklahoma DOT. Other work includes:

The work is made possible in part due to $95 million in funding from two federal grants as part of the Infrastructure Investment and Jobs Act: An $85 million Mega Grant, which supports large, complex projects that are difficult to fund by other means, and a $10 million RAISE Grant, which funds surface transportation projects that have a considerable impact at the local or regional level.

The project is expected to be complete by summer 2028, weather permitting, per Oklahoma DOT. A future project will complete the widening of I-44 between the I-44/I-244 Western Split and the Arkansas River.

This is just one of 1,647 projects planned for the state over the next eight years, according to the Oklahoma DOT’s 2025-2032 Eight-Year Construction Work Plan, which designates $8.6 billion to a variety of road and bridge efforts throughout the state.