The long-awaited opening of the Interstate 540 extension has been delayed again.

The new 7½-mile stretch from U.S. Highway 64 to Capital Boulevard was scheduled to open before the first of the year, but project leaders said Thursday that isn't going to happen. Drivers will have to wait at least another month to travel the new stretch of I-540.

Project leaders said they hope open the new roadway by the last week in January, but they aren't making any promises.

"I'm a little disappointed. I was hoping that would open pretty soon," said Bret Owen, a driver who plans to use the new extension once it's finished for his daily travel to work at Research Triangle Park.

"I don't understand why it's taken so long. Why can't they go and speed it up?" said Carla Jones of Clayton.

The multimillion-dollar project has hit some roadblocks. Officials said that building a highway through environmentally sensitive land has been one of the biggest challenges for the project.

The extension has been under construction for more than three years. The opening has been delayed more than once, and the price tag has been driven up by those delays. The $67 million project now totals $73 million.

"It's kind of typical, I guess, but unfortunately I think that's the way it goes with some of the road construction projects sometimes. I know sometimes there are a lot of hidden costs. I guess that's the price of growth sometimes," said Cory Jenkins, a driver who told WRAL he's anxious to see the project complete.

Crews have been working seven days a week to get the job done. Paving on Dec. 16 around the Capital Boulevard interchange, currently the end of the interstate, created backups of two hours for residents and holiday shoppers trying to get to several retail centers in the area.

"I'll just have to wait a little longer. but I'm still looking forward to it opening," said Owens.

State officials said they are busy trying to tie up some last-minute loose ends. The contractor hired to do the project could face a fine up $10,000 a day for each day the project falls behind schedule. But state officials told WRAL that many of the delays were out of the contractor's hands.