The Fairfax County Board of Supervisors, calling Capital Beltway tractor-trailer accidents "one of the most serious problems facing Northern Virginia," voted unanimously yesterday to ask Gov. Charles S. Robb for a "comprehensive plan" to reduce accidents and a strategy to relieve resulting traffic jams.

George Stoddart, press secretary to the governor, said late yesterday he had not yet heard of the board's vote.

He said the matter would be referred to Robb's secretaries for public safety and transportation, Franklin W. White and Andrew B. Fogarty.

Virginia State Police have increased the number of troopers patrolling the Beltway in response to as many as 10 complaints a day about reckless truck drivers.

Trucks were involved in 116 of the 448 accidents on the Beltway in Virginia during the first nine months of this year.

State Police Lt. Herbert D. Northern, acting commander of the Northern Virginia Division, said he welcomes "anything or any suggestions that will answer the problem on the Beltway" but that state police will need new laws and more troopers to make the road safer and change the way accidents are handled.

Board Chairman John F. Herrity, who was stranded in a Sunday evening Beltway backup near the Telegraph Road interchange, complained that some state police spent their time writing summonses for motorists using the emergency lane instead of helping frustrated drivers find ways around the tie-up.

Sunday's backup, stretching from the Woodrow Wilson Bridge to Van Dorn Street, began about 4:30 and lasted until 7 p.m., police said.

It was caused by several accidents in Maryland, as well as one in Virginia, and was exacerbated by two bridge raisings, police said.

State Police Sgt. William D. Carter said police did not ticket motorists on the emergency lane, and that Herrity probably witnessed the aftermath of a minor collision between a motorcycle and a squad car, handled by two troopers and a sergeant.

Carter and Northern said it is illegal for non-emergency vehicles to use the emergency lane and that to change the practice would require a change in state law.

"It may be that for temporary problems, traffic could be moved onto those shoulders.

It's something worth looking into," Northern said.

Police also said they need more troopers if the public wants them to help detour traffic off the Beltway. Otherwise, they said, vehicles would back up at the bottoms of exit ramps -- because of either signal lights or lost motorists.

Northern could not say how many more troopers might be needed to provide the additional service because each accident and Beltway location is different.

State police are using 12 troopers instead of the usual four to patrol Virginia's 23-mile stretch of Beltway. Patrols will operate in marked and unmarked cars between 7 a.m. and 11 p.m. in a one-month experiment designed to reduce tailgating, speeding and other causes of accidents.

The results will be evaluated in November.

This month, the state highway commission is scheduled to reconsider it's decision of several weeks ago not to ban trucks from the Beltway's left lane.