Overriding the strong objections of area residents, the Fairfax County Board of Supervisors approved yesterday a controversial zoning change that will allow increased development on a 930-acre tract near the Lorton prison complex.

The decision paves the way for John T. (Til) Hazel Jr., one of the most prominent developers in Northern Virginia, to build a cluster housing development on 256 acres of the parcel, a triangular property bordered by Silverbrook, Ox and Hooes roads.

The 6-to-2 vote on the so-called Silverbrook development followed a heated debate during which numerous residents argued that construction in the already congested area of southern Fairfax County would increase traffic, aggravate school crowding problems and pose safety risks for the new homeowners.

But the majority of the supervisors contended there was little they could do to stop construction at the site and that the most attractive option was to approve the planned development proposed by Hazel.

"It seems to me we can't do anything but improve the area by going ahead with the change," said Supervisor T. Farrell Egge (R-Mount Vernon). "In the long run, this is the best option for this particular piece of property."

"We cannot stop this just because there's a prison there and just because there's traffic there," agreed Supervisor Elaine N. McConnell (R-Springfield).

Supervisor Audrey Moore (D-Annandale), an outspoken critic of the project, said, "We're talking about an area where we've got a real safety threat. The overwhelming issue here is that you're next to the prison, a prison that has demonstrated significant problems." Voting with Moore to reject the proposed development was Supervisor James M. Scott (D-Providence). Supervisor Martha V. Pennino (D-Centreville) was absent during the vote.

In return for the greater density, Hazel promised to donate an $800,000 site to the county for construction of an elementary school on the 930-acre tract. Hazel also pledged to donate a park to the county, to protect the stream bed that runs through the property and to build a sewer line that would serve the neighborhood and others in the area.

Some residents from nearby neighborhoods asked why supervisors were abandoning their much-publicized concerns about placing people near the prison.

Board of Supervisors Chairman John F. Herrity, one of the most vocal critics of the prison, said he had no power to stop construction on the disputed tract. "No matter what we do here today, there will be a development by the prison," he said.

In another development-related matter yesterday, the board once again postponed its decision on the Westfields project, a proposed 1,048-acre development that is expected to be one of the largest commercial and office centers in the county.

The supervisors tabled the issue until next Monday's meeting because the developer, the Henry A. Long Co., failed to supply the county with a list of people belonging to the numerous partnerships involved in the project.

Westfields, which is slated to be built along the section of Rte. 28 that sweeps past the Dulles International Airport at the western edge of the county, is seen by local officials as a catalyst for development in what is commonly known as the Dulles corridor.

Critics of the development contend that it will add to the traffic problems along that stretch of Rte. 28, a key north-south artery that runs through Fairfax, Loudoun and Prince William counties.

In other action yesterday, the board urged the Virginia General Assembly to beef up the state police force in Northern Virginia.

A consultant's report released recently recommends that Fairfax, which is now assigned 41 state troopers, get an additional 15. The report urges the state to increase Arlington's number of troopers to 65 from the 35 now authorized. The troopers would be deployed on the interstate highways that run through Northern Virginia, including the Capital Beltway, Shirley Highway and I-66.

The board also gave preliminary support to a plan to pay for a one-year commuter rail service from Fredericksburg, Va., to the District. The service, which would run for a year on an experimental basis, has to gain approval from other Northern Virginia localities and clear a number of other financial hurdles before it can get under way.