The Federal Aviation Administration yesterday said it will consider easing its tight grip on use of the Dulles Access Highway to allow single-occupant vehicles to use the restricted road during rush hours.

The action broadens a proposal the FAA offered earlier this summer to loosen the current restrictions on the federally owned highway by allowing two- or three-member car pools to join four-member car pools using the highway, which is currently restricted to the car pool vehicles, buses and traffic to and from Dulles International Airport.

Officials in both the FAA and local governments said the agency, which has long sought to limit commuter use of the road, is seriously considering the more liberal proposal, put forth by Rep. Frank R. Wolf (R-Va.) after the agency's initial proposal June 6. The FAA must consider public reaction to the various proposals before it can issue new rules for the highway.

Public comment on the two-member car pool proposal has run 4 to 1 in favor of liberalization, according to a congressional official who has examined the comments.

Upwards of 8,000 cars a day, many of them residents of the fast-growing Reston and eastern Loudoun County areas, have been skirting the current regulations by "backtracking" on the access road to the Dulles terminal and then driving east with airport traffic. The highway has only two eastbound access ramps, and both are guarded.

The road is extremely popular with commuters because it allows them to whisk past time-consuming tie-ups, particularly in the Tysons Corner area.

Regardless of what the FAA decides, some relief for commuters should come in October 1984 when Virginia highway officials open a four-lane toll road parallel to the Dulles highway. At that time, the FAA once again will restrict use of the Dulles highway to traffic to and from the airport.

"The point is to convenience these people until the commuter toll road is open, and to even liberalize the current restrictions a little bit," said David Hess, a spokesman for the FAA's Metropolitan Washington Airports agency. "Essentially," he said, "this would permit the people who are currently illegally using the Dulles access by backtracking to continue using it."

Under the options FAA is considering, commuters would get a sticker that would allow their vehicles access to the highway during rush hour. Despite the language of the FAA proposal, printed yesterday in the Ferderal Register, Hess said single drivers from Reston still will have to backtrack through the airport. Two- and three-person car pools could enter the highway at Reston Avenue or Trap Road and head directly east.

"This provides the alternative of one person going all the way to the airport with a permit, or forming a two- and three-person car pool and using those," Hess said. "It does not permit single-occupant vehicles to go on and off at Reston and Trap."

Yesterday's notice makes no mention of such restrictions on single-occupant cars. The notice says the FAA is considering "the alternative of authorizing all commuter vehicles to use the Access Highway with a decal regardless of the number of occupants in the vehicles. Essentially, vehicles with a decal would be permitted to enter the Access Highway at one or more locations."

Hess said, however, that FAA lawyers interpret that language to restrict the single-rider cars to backtracking, a problem that local officials have said would be virtually impossible.

In broadening the scope of the proposals, the FAA also reopened the public-comment period until Sept. 1. After that the FAA will review the comments before issuing final rules sometime in the fall.

A spokesman for Wolf said he is pleased with the FAA's action and said he "hopes his proposal will ultimately be selected."

John F. Herrity, chairman of the Fairfax County Board of Supervisors, said, "I think it's an appropriate thing for them to put forward for people to comment on. . . . I would not oppose it."

Any liberalization likely will take effect after a road opens linking the access highway to I-66 inside the Capital Beltway. Commuters who do not meet the I-66 four-member car pool requirements during its rush hours will have to exit the Dulles highway at either the beltway or Dolly Madison Blvd.

A spokesman for the Virginia state highway department said the four-person restriction on I-66 will be reviewed this fall, after the Dulles connector is opened.