The Dulles Airport Access Highway will be opened "on an interim basis" to carpools carrying two persons or more during rush hours this summer, possibly as early as June, according to an agreement worked out between the U.S. Department of Transportation and Rep. Frank R. Wolf (R-Va.).

In addition, "backtracking"--driving west to the airport terminal from Reston on the access road and then returning east -- will be permitted for cars carrying as few as two riders. Travel on the access road is now restricted to airport traffic except during rush hours when four-person carpools and buses are allowed to travel east from Reston.

Wolf announced yesterday that his proposal to permit expanded use of the Dulles road had been approved by Transportation Secretary Elizabeth H. Dole as a way of easing area commuter problems until the Dulles Toll Road is completed in late 1984.

"We're the only area in the country with the four-person carpool restriction," said Wolf, who has lobbied to cut those restrictions on Shirley Highway and Interstate Rte. 66. "Other areas have two- and three-person carpooling requirements."

State highway officials said this week that they will ease carpool restrictions on Shirley Highway on an experimental basis, permitting three-person carpools during certain periods of the morning rush hours.

The state and officials in Fairfax and Loudoun counties must still approve arrangements for easing commuter restrictions on the Dulles access road, including the issuance of stickers to identify access highway traffic. Wolf said he is confident the details can be worked out by June.

"The road is so underused now that there will be no problem with access to the airport," said Wolf. He said his plan will ease congestion on Northern Virginia's back roads and in the Tysons Corner area and help commuters from the Sterling Park, Sugarland Run, Vienna, Reston and Herndon communities.

Wolf said the modified backtracking provision in his plan is an attempt to help commuters this summer, when the federal government is expected to crack down on backtracking.

The major stumbling block in opening the access highway completely, Wolf said, is Virginia's inability to separate access highway traffic from traffic on I-66, where rush-hour cars must carry four riders. This fall, the access road will connect to I-66 at the Capital Beltway.