The Fairfax County Board of Supervisors took the first step yesterday toward adding toll lanes for local traffic alongside the Dulles Airport access road, which now is almost totally restricted to airport traffic.

By a vote of 8 to 1, with Supervisor Audrey Moore (D-Annandale) dissenting, the board accepted County Executive J. Hamilton Lambert's proposal to spend $1.5 million to design the 13-mile facility. If built, financed by revenue bonds repaid from the tolls it would yield, it would be the only toll highway in the Washington area.

The new lanes would cost an estimated $54 million. Construction would be expected to start in September and take two years.

The existing Dulles road permits traffic between the Capital Beltway and the airport, without ramps to and from intervening communities except for buses serving Reston and traffic to and from seasonal events at the Wolf Trap Farm Park, where the Filene pavilion was destroyed by fire Sunday evening.

When the Dulles road was built for the airport's opening in 1962, space was left alongside for a local-service road as well as for possible rapid transit in the median strip. Supervisors voting for yesterday's measure said the toll lanes would ease congestion at Tysons Corner, reduce commuting time and spur economic development.