The agency previously said construction would be finished in time for the 2025 North Carolina State Fair.
The ongoing work is leaving people who live along the corridor frustrated.
"(It's a) never-ending annoyance," said Raleigh resident Hannah Adamson. "We don't know when this is going to end."
Driving little ones to and from school takes longer.
"If you're running maybe 30 seconds behind, 2 minutes behind - you're adding on about 15 minutes to your drive to school," she said.
Adamson said she's had to pay out of pocket a couple of times for car repairs.
"I've had a flat tire. My sister has had a flat tire (and my) husband," said Adamson. "There's debris all in the road at all times."
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The DOT is upgrading the corridor and making other improvements, such as placing the road under the railroad tracks near the State Fairgrounds.
The work was estimated to cost $475 million.
The NCDOT said there was a lot of utility infrastructure to move, and the process of acquiring land took longer. There were also issues with the soil.
"That really put us back, because we spent a lot of time repairing soil that we didn't anticipate having a problem with, to begin with. Then, of course, there is weather. We had a lot of weather issues and a lot of weather delays," said NCDOT Spokesperson Kim Deanor.
The work is now expected to be done by the end of 2026.
"It's definitely going to be worth the investment," said Deanor. "We're going to give people a way to get across from Hillsborough - make their way out of Carter Finley, out of the Fairgrounds, the Lenovo Center - in a safe way."
Simultaneously, the City of Raleigh is also working to make improvements on Blue Ridge from Duraleigh Road up to Crabtree Valley Avenue.
The city said work on the improvements is on schedule.