The construction of toll lanes alongside the 13-mile, limited-access Dulles Airport Access Road would be financially feasible, a consultant's study commissioned by the Virginia highway department has concluded.

That conclusion apparently clears the only major hurdle to construction of the lanes, which could trigger an industrial boom, similar to the one on I-270 in Montgomery County, in the corrideo from Dulles to Tysons Coner, often called Fairfax's downtown.

The toll lanes also could accelerate the already rapid residential development in western Fairfax and eastern Loudoun County, straining already overburdened public facilities.

The Virginia Highway Commission is expected to consider the toll-road issue at its next meeting, Dec. 7, and a highway department spokesman said the commission "would probably act favorably" on the proposal.

JHK Associates of Alexandria, which analyzed the proposal for the state, said the paralle lanes - two on each side of the present road, which generally is limited to airport traffic and commuter buses - could be built by 1985 for $57 million obtained through sales of bonds and paid for with revenue from tolls within 25 years.

The study suggested a 50-cent fare for the full trip and less for intermediate ones. For example, a Reston commuter would pay 35 cents to go to Tysons Corner.

Motorists bound for Arlington or Washington would be able to continue on a nontoll spur that would connect with the extension of I-66, now under construction and running from the Capital Beltway to the Theodore Roosevelt Bridge. The spur and the I-66 extension are scheduled to be finished by 1985.

The toll lanes would relieve a major transportation bottleneck in Fairfax. Most eastbound traffic from northwestern Fairfax and eastern Loudoun has to be funneled to Leesburg Pike (Rte. 7). The small end of the funnel is at Tysons Corner, where horrendous traffic jams build up, especially but not exclusively during commuter hours.

It is not unusual for a solid line of cars to be inching along from Tysons Corner to as far west as Colvin Run Road, a stretch of about 5 miles.

Reston residents, led by their supervisor, Martha V. Pennino, have long pressured the Federal Aviation Administration to open the present Dulles road to all commuter traffic, but the FAA, which owns the highway, has said no. The toll road suggestion was a compromise proposed by the Virginia Department of Highways and Transportation.

Poor transportation links from the Dulles area to Tysons Corner and beyond to Washington have been cited as a main reason why an expected surge in industrial development near the airport and nearby Herndon and Reston never materialized.

The tolls lanes, which would provide the missing access, would have interchanges at Sully Road (Rte. 28), Herndon, the proposed Springfield Bypass (between Reston and Herndon), Reston (three) and just west of Tysons Corner at Springhill Road.

The study said the road would cost $57 million and be paid for in 25 years if the state accepted the costs of collecting tolls and maintaining the road - as it does for the two existing such highways in Virginia, from Richmond to Pertersburg and from Virginia Beach to Norfolk. Without the state contribution, the cost would be $60 million and would be spread over 35 years because of higher interest.

In another move concerned with the county's future development, the Fairfax Board of Supervisors set public hearings yesterday on staff proposals calling for less dense development in the northwest corner of the county above Herndon and Reston as well as in the watershed draining into the Occoqual Reservoir, drinking-water sourve for 600,000 Northern Virginians.