Drivers who have endured roadwork, cones and barricades on and around rough and aging Pu'uloa Road in Salt Lake for more than 18 months will have to wait about another year for the construction to be completed.

The extensive Pu'uloa Road improvement project began in July 2005 to address a number of long-standing problems and was supposed to be finished this summer.

But the discovery of uncharted, shallow underground utility lines has pushed back the completion date to spring of next year, said state Department of Transportation spokesman Scott Ishikawa.

Moving the utility lines is expected to add $3 million to the project's original $18.4 million cost.

Salt Lake residents and others who use the road were disappointed by the delay.

"It's kind of frustrating, because the project has been going on for a while," said Salt Lake resident Kevin Littlejohn. "And the fact that it is an obstruction, it is frustrating sometimes trying to get through there. ... In the busy parts of the day ... it's a mess."

Pu'uloa has long been a patchwork of potholes that makes for a teeth-jarring ride — with no lighting or drainage, making driving at night or after a heavy rain an even more hazardous venture.

Traffic still quickly backs up when vehicles try to make left turns, and many drivers have resorted to taking side streets to avoid the bumpy, narrow road.

Pu'uloa is heavily used, to get to and from the Mapunapuna industrial area and between Salt Lake and Nimitz Highway. The road's busiest point, the intersection with Salt Lake Boulevard, was used by more than 37,000 cars a day in 2005, according to the state Transportation Department.

The project involves widening Pu'uloa Road from Nimitz Highway to Salt Lake Boulevard and putting in drainage, lighting, bicycle lanes, sidewalks and left-turn lanes at busy intersections. Other improvements include resurfacing, landscaping and a paved 80-stall parking lot on the 'ewa side of the road.

Ishikawa said the utility lines conflict with the planned drainage system, and officials also need to make room for new utility lines being placed underground as part of the project.

"So we have to carefully relocate them before we move ahead with the construction," he said.

Work on the Salt Lake Boulevard/Pu'uloa Road intersection will run at night from March to May. The next phase of work on Pu'uloa Road will begin this summer, during which time traffic will be temporarily diverted to the new parking lot area on the 'ewa side of the road, Ishikawa said.

Kris Hara, who lives in the Moanalua Gardens area, uses Pu'uloa Road less since the project began because "the road's deteriorated even more ... and it seems very unsafe now because they really narrowed the roadways."

"I'm disappointed, but I understand that perhaps it was unforeseen," she said. "So we just have to be patient."

Reach Lynda Arakawa at larakawa@honoluluadvertiser.com.