The reconstruction of the Springfield interchange, the region's largest highway project, is now scheduled to last at least 9 1/2 years, though Virginia officials promised when the work began that it would be completed in no more than eight.

That raises the prospect that many of the 375,000 motorists who each day navigate the Northern Virginia crossroads known as the "mixing bowl" could face construction delays for longer than they now dread.

Top state transportation officials repeated their pledge yesterday to uphold the eight-year time frame, though under recent revisions to the state's highway blueprint, the state plans to finish the third of four construction stages in fall 2008, or 9 1/2 years after the undertaking began this past spring. There is no date set for completing the entire project.

Several reasons were cited for the early schedule changes: First, dozens of properties adjacent to the site were not acquired by the time the contractor started the first stage, making that work more difficult. Second, unexpected difficulties in designing and financing construction of the next stage forced planners to delay the start for two years.

Officials acknowledged that the new plan stretches out the timetable, but Transportation Secretary Shirley Ybarra and Acting Highway Commissioner Charles D. "Chip" Nottingham vowed yesterday to make up for the delays by accelerating the later phases of construction.

"The project will be completed in the spring of 2007 barring a terrible act of nature or earthquake or something we can't control," Nottingham said.

Nottingham acknowledged that cash flow considerations contributed to the second-stage delay but pledged that sufficient funds would be found to complete the overall project on time.

As recently as last week, Gov. James S. Gilmore III (R) assured Northern Virginia business leaders that the project was proceeding smoothly. "It's being done very fast. It's not behind schedule. I think it's a little ahead of schedule, to tell you the truth," he said in a speech to the Fairfax County Chamber of Commerce.

But the problems so early in the $400 million project have raised fears among Northern Virginia officials from both parties about whether the Virginia Department of Transportation can deliver the project on time.

"I think it's unfortunate for people who are living there that they have not been told the truth all along," said Del. Linda T. "Toddy" Puller (D-Fairfax), who is running for a state Senate seat. "It worries me that an eight-year project is now becoming a 9 1/2-year project and we're not very far into it."

The effort to rebuild the treacherous interchange, where the Capital Beltway and Shirley Highway intersect, ran into difficulties even before construction began. The state instructed the contractor, Shirley Contracting Corp., to proceed with construction in April, though VDOT had not yet acquired 61 adjacent properties needed for the initial stages of work. The contractor has been forced to substantially revise its work program.

Soon after this initial stage began in April, the state issued a new timetable for completing the remaining phases of the project, including a two-year delay in the second stage, which had been scheduled to start this past summer. At first, VDOT officials said the change was made because they were concerned about having several contractors working on the project simultaneously.

"We wanted to see if all the work . . . was going smoothly and not have any problems with contractors being on top of each other," said Dewey Litton, VDOT's manager for the Springfield project.

Several officials and highway experts said this should not have been a problem.

Paul H. Templeton, chief highway engineer with HNTB Corp., which is designing the project, said an overlap between the two stages should pose little difficulty, because they are in separate locations.

"The jobs are separated," said Richard Daugherity, executive vice president of the Virginia Road and Transportation Builders Association. "I don't believe that having two contractors do work up there really presents a problem." He said VDOT has previously engaged multiple contractors to work simultaneously on highway projects.

In recent days, VDOT officials said two other factors were largely responsible for delaying the second stage: a shortfall in funding and significant revisions in the plans.

"A lot of things didn't get completed in time for the original timetable," said Mike Heflin, VDOT senior land acquisition agent. "The plan was not ready for construction as early as they had anticipated."

He said engineering plans had to be redone because they did not provide for the considerable number of telephone and other utility lines that would have to be relocated. Until the plans were finished, VDOT could not acquire much of the land needed for the upcoming phase, he said. "We wouldn't have been able to meet the 1999 timetable," he said.

Meanwhile, cash-flow problems at VDOT raised the prospect that construction could be delayed even after the plans are revised and property obtained.

James W. Atwell, assistant highway commissioner for finance, said the department was forced in the spring to delay the scheduled start of the second stage for two years after the projected cost rose from $70 million to $90 million. Under department guidelines, VDOT bids a project once 70 percent of the construction funds are in hand. The higher cost meant it would take two years longer to reach that threshold.

Officials were unwilling to breach their financial guidelines, Atwell said. "During times of tight cash-flow situations, we make sure we comply with the business rules," he said.

In the spring, as the state was postponing the second stage, officials were also setting the schedule for subsequent construction. The plan adopted by the Commonwealth Transportation Board calls for the third stage to begin in fall 2004 and end in fall 2008.

Litton said he expects the state will accelerate the project's later work and complete all but the last stage within eight years. He said this could be done by starting the third stage a year earlier and offering the contractor a bonus if it finishes ahead of time.

"It is a commitment that the secretary of transportation and the governor made: We are going to build this in eight years," Litton said. "I feel confident it will be done. We will tighten down the time line."

This time line, however, does not include the fourth and final stage: a $37 million job to build car-pool lane ramps linking Shirley Highway and the Beltway. State officials say the timing depends on a separate project to widen the Beltway. Litton said VDOT had never meant to imply that this work would be completed within the eight-year deadline.

In comments preceding the groundbreaking in the spring, however, state officials consistently included the car-pool ramps as part of the Springfield interchange project and said that all work would be finished in eight years. VDOT's Web site also presented the same time frame: "Completion of all phases could take up to 8 years."

CAPTION: Construction of the Springfield interchange is viewed from the top of the Holiday Inn Express, looking at I-95 southbound and the Franconia Road overpass.