The Northern Virginia Board of Realtors and the Northern Virginia Builders Association have voiced strong support for Fairfax County's $134 million road bond referendum this fall.

Both organizations said their membership and the businesses they represent would benefit if county voters approved the bond issue. Industry sources said the planned road improvements are keys to the growth of Fairfax County.

Scott McGeary, legislative assistant for the builders group, said the referendum "is critical" to the life style available to those living in Northern Virginia.

William Laughlin, vice president of the Northern Virginia Board of Realtors, promised the Fairfax Board of Supervisors that the 8,655 members of the Realtors' group will support the bond referendum.

"Most of our members sell real estate for a living. They drive these roads every day. They know, better than many, the problems that this issue addresses. They understand better than many the magnitude of the need for action now," Laughlin said.

McGeary said the NVBA strongly supports the road bond referendum.

Even though Laughlin said he had not yet polled the entire NVBR membership, "I believe county road bonds to be one of the most significant issues in the minds of our membership."

He said most Realtors "appreciate that there are areas of Fairfax County that will not immediately benefit from this bond issue" in terms of new or improved roads near their homes.

"We believe, however, that since few of us live, shop, play and work in the same magisterial district, all citizens of Fairfax" will benefit from what he called a "broadly based effort to improve our ability to get from where we are to where we want to be."

McGeary said voter approval "is crucial to the future of Fairfax County."

County officials and building and real estate industry officials say the road improvements are necessary because of the county's continuing boom in residential and commercial development. Fairfax board Chairman Jack Herrity and other members of the board of supervisors have promised to promote the bond program almost as if it were a major political campaign.

During a recent interview, Herrity said many people do not realize that "50 percent of the people don't leave the county" to go to work. This is a dramatic change from when Fairfax was considered a bedroom community providing the labor force for the District. Today, many of the major traffic problems are generated by commuters trying to crisscross Fairfax County rather than get out of the county, transportation officials said.

The top priority on the bond referendum is constructing two major segments of the Springfield Bypass, which is designed to connect western Fairfax with the Route 1 corridor. Funds allocated on the proposed bond issue for the bypass total more than $87 million. That money would be spent on a segment of the bypass from Route 50 to the Dulles road corridor and on another piece between Rolling Road to Beulah Road in southeast Fairfax. That stretch of the bypass would cross I-95.

Also on the referendum in the southern part of the county are $13 million for the extension of South Van Dorn Street to Lockheed Boulevard, $2.9 million to make South Van Dorn Street a six-lane divided road from Franconia Road to I-95 and $5.4 million to widen Telegraph Road from Franconia Road to I-95.

In the Oakton-Fairfax City area, the bond issue calls for $12 million to make Blake Lane a four-lane divided road from Jermantown to Route 50 near Pickett Road.

The bond issue also includes money to make the following improvements:

* Changing the Route 7/Baron Cameron Avenue intersection, which is the main entrance to the Reston area from Route 7, at a cost of $470,000.

* Widening Guinea Road in the Braddock Road-Twinbrook area at a cost of $3.9 million.

* Improving the intersection of Old Dominion Drive and Dolley Madison Boulevard in McLean at a cost of $1.5 million.

* Improving South George Mason Drive from Leesburg Pike to the Arlington line at a cost of $1.4 million.

* Improving John Marr Drive from Ravensworth Road to Backlick Road at a cost of $1 million.

The referendum also calls for improvements to the intersection of Franconia Road and Commerce Street and for making Gosnell Road in the Tysons Corner area four lanes between Dawson Street and Old Courthouse Road.