A new expressway that would snake through the hub of eastern Prince William County would bring relief to one of Northern Virginia's most congested areas and open 1,000 acres for commercial development, county officials said yesterday.

In a unanimous vote yesterday, the Board of County Supervisors directed county transportation officials to continue planning for the so-called Prince William Parkway, which would connect I-95 with the county's booming Dale City area near the Potomac Mills discount mall on Smoketown Road near Davis Ford Road.

Prince William officials said the approximately mile-long route could transform what now includes an enormous automobile junkyard on Smoketown Road into the "Main Street" of a gleaming economic development corridor, bringing millions of dollars in tax revenue.

If the road were built, the most likely way to pay for it would be with a special property tax surcharge on developers whose land would benefit from the road's construction, according to county transportation planner John Schofield.

Similar funding schemes, authorized by the Virginia General Assembly last winter, are being discussed for the proposed expansion of Rte. 28 near Dulles International Airport and a proposed Rte. 234 Bypass around Manassas.

Schofield said the Woodbridge-Dale City area may have the same combination of constituencies as the other areas: a general public outraged by traffic congestion, and private developers who know their land has little value if new roads are not built.

"The parkway represents a recognition of the changing face of Prince William County as we grow to meet the economic development goals" that have been repeatedly endorsed by the supervisors, Schofield said.

Under the most optimistic scenario, Schofield said, construction on the Prince William Parkway would begin next year and be completed at a cost of $7 million to $9 million in 1990.

While county officials pushed ahead on planning for the parkway, they also heard from angry residents opposed to the expansion of another key road in the same area.

Despite the opposition, the supervisors voted unanimously last night to condemn property on a portion of Smoketown Road to expand the route into a four-lane divided highway. The supervisors also agreed to meet with state legislators and transportation officials in an effort to find ways to lessen the impact of the road expansion on homeowners in the Rollingwood Village subdivision.

At a public hearing before the vote, residents of the subdivision lashed out at a proposal to condemn land in the back yards of about 16 households in order to widen Smoketown Road north of Davis Ford. The developer has agreed to pay for the road expansion, which is required to bring that portion of Smoketown into the state highway network. County officials have labeled the project a priority, but landowners have refused to yield.

Officials said the condemnation would be temporary, lasting only during construction of the new lanes. But the propertyowners said the road expansion would mar their land and accelerate the transformation of their portion of Smoketown from a residential street into a major thoroughfare.

"Are we a residential area, which is what I bought my house in, or are we a {traffic} 'corridor,' " asked Judith Bean, one of the angry Rollingwood Village residents. Bean said she worried that speed limits on Smoketown won't be enforced until someone is killed or injured in a crash. "God help all of you that it isn't one of my kids," Bean told the supervisors, to a burst of applause.

Some county officials said that at least some of the residents' frustration is justified: the developers' plans to expand the road, they said, have repeatedly been delayed and revised, creating an air of mistrust in the community.

The officials emphasized, however, their belief that the expansion of Smoketown Road will benefit all of Prince William, most of all the 3,000 homeowners in Rollingwood Village, who will gain the benefits of state maintenance of their roads.

Under a condemnation, a judge must rule on what is a fair price.

In other action, the board voted to close portions of three dead-end streets in eastern Prince William's Marumsco Hills community. Residents complained that Lancaster, Surrey and Sharp drives had become meeting places for unruly youths.