The Fairfax County Board of Supervisors gave final approval last night to a spring referendum on sale of $150 million in bonds -- the largest bond referendum ever in the county -- to finance roads, parking facilities and other transportation-related projects.

The April 12 referendum was championed by Board Chairman Audrey Moore and other supervisors in their election campaigns last year.

Among projects the bond sale would finance are two stretches of the crosscounty Springfield bypass costing $31.2 million, the Rte. 50-West Ox Road interchange costing $14.8 million and the South Van Dorn Street-Capital Beltway interchange costing $15.3 million.

The referendum was approved by an 8-to-1 vote after a four-hour public hearing at which 60 people testified, most in favor of the bond sale and many advocating pet projects in and around their neighborhoods.

County officials said, however, that projects for the referendum were not selected with an eye toward distributing them evenly around the county, but rather on the basis of how they complemented state and county road improvements already built or in early stages.

The main criterion in selecting the projects was how quickly they could be completed. Officials said the majority of projects included in the bond sale voters will be asked to approve could be started within 18 months, with the bond money spent and all roads on the list completed within three years.

Supervisor Elaine McConnell (R-Springfield) was the only one to vote against the referendum, and she did so despite a board decision to designate $3 million for improvements to Braddock Road, which is in her district. McConnell said the reason she voted no was "because Keene Mill Road got left out . . . Keene Mill Road got nothing from Audrey Moore but a betrayal."

Moore said, "I think the board acted tonight to distribute the money around the county a little more uniformly . . . . The average person stuck in traffic going to his job is going to support this. They were here tonight to tell us so."

Officials said voter approval of the bond sale would not lead to an increase in any tax rate.

County voters have overwhelmingly approved road bond sales totaling $190 million at three referendums since the county got authority from the legislature in 1981 to finance its roads. About $122.5 million of the bonds that were authorized remain unsold, primarily because projects have been delayed by such things as problems with land acquisition and environmental concerns.

For example, sale of $90 million in bonds has been authorized for work on the 35-mile Springfield bypass, the county's number one transportation priority. Only $10 million of those bonds have been sold because of delays in design and land acquisition by the state, according to county officials.

Yesterday afternoon, the board gave the go-ahead for sale of about $100 million in previously authorized bonds for schools, parks, storm drains and roads at the end of March.