A Fairfax County couple, whose 20-year-old son was killed by a man charged with driving while intoxicated, has gained the support of the Board of Supervisors in a campaign to toughen Virginia's drunken driving laws.

Marie A. Kunec and her husband Edward have collected 3,200 signatures on petitions asking Charles S. Robb, Virginia's governor-elect, to set up a task force to study the possibility of strengthening the state's drunken driving laws.

Kunec, a housewife whose petition drive is being aided by the California-based group MADD (Mothers Against Drunk Drivers), said she has received letters of support from several state politicians, including state Sen. Adelard L. Brault (D-Fairfax) and Del. Bernard S. Cohen (D-Alexandria).

She also said that Del. Vincent F. Callahan Jr. (R-Fairfax) told her he plans to introduce legislation in the next session of the General Assembly to strengthen the state's drunken driving laws.

On Monday members of the Fairfax board endorsed Kunec's proposal and sent a letter to Robb supporting the creation of a state task force on drunken driving. Included in the board's resolution was a proposal to examine the prosecution of drunken drivers in Fairfax County.

Drunken drivers were responsible for about 10 percent of Virginia's 1,231 highway fatalities in 1980 and were involved in 25 percent of the state's 161,059 highway accidents, according to state police.

The Kunec's son, Edward Jude, died at the University of Maryland Hospital in Baltimore from injuries he received in a highway accident July 12.

He was a passenger in a car that was involved in a minor accident on U.S. 29 just outside the Merriweather Post Pavilion in Columbia. Edward Jude Kunec was standing behind the car in which he had been riding when he was struck by a third vehicle. The driver of that vehicle was scheduled for trial Dec. 28 on charges of speeding, reckless driving and driving while intoxicated, but the trial has been postponed to Jan. 29 because the police investigation has not yet been completed.

"The judges are being too lenient," said Marie Kunec, who has three daughters and a 13-year-old son. "While we are not experts on the subject, we feel that the judges should have no discretion in sentencing when a person is convicted of drunken driving.

"A lot of people think a good deterrent would be to publish the names of people convicted of drunken driving in the newspaper," Kunec said. Her group also supports suspending a person's driver's license on the first drunken driving conviction and revoking the licenses of multiple violators.