Intersection improvement project underway at I-35, SH-9W in McClain Co.

A major intersection improvement project is underway at the I-35 and SH-9W interchange near Norman in McClain Co. The project consists of a number of improvements including reconstructing the current interchange into Oklahoma’s third Diverging Diamond Interchange, widening I-35 to six lanes between SH-9W and Main St. in Goldsby and building two roundabouts along SH-9W service roads. Work is expected to be completed in 2026.

Two lanes of traffic will remain open during construction; however, drivers should be prepared for intermittent lane narrowing and temporary lane shifts from 9 p.m. to 6 a.m. Monday through Friday as well as 9 a.m. to 6 p.m. Saturday and Sunday throughout the project.

Drivers are urged to give full attention to the road during construction and watch for Smart Work Zone message boards that will provide advanced traffic warnings during work.

Once completed, drivers will experience a new traffic configuration on SH-9W at I-35. Signage, signals and pavement markings will guide drivers through the intersection, which will briefly take east and westbound traffic to the opposite side of the road. Drivers will also experience six lanes of I-35 providing more traffic flow and travel time reliability.

The Oklahoma Transportation Commission awarded the $105 million project to Sherwood Construction in August 2023.

Oklahoma's first Diverging Diamond Interchange opened in September 2020 at the I-40 and SH-6 interchange in Elk City. DDIs offer a proven solution for improving traffic flow and safety at interchanges.

Facts about DDIs:

• The first DDI in the U.S. was constructed in Springfield, Mo., in 2009.
• Create safer, less congested intersections.
• Allow for fewer conflict (collision) points.
• Give drivers better sight distance at turns.
• Pedestrian crossings are shorter.
• Aim to eliminate left turns across traffic and thereby increase safety.
• Give "free-flowing" or simple left- and right-hand turns from all directions.
• Wrong way entry to ramps becomes extremely difficult.