It was, as they say in politics, a great photo opportunity: Rep. Frank R. Wolf (R-Va.), standing at the edge of traffic-snarled George Washington Parkway last Thursday afternoon, talking to unhappy commuters about his proposal to widen the road.

A little corny, perhaps, but it was a significant event in the Washington suburbs, where hour-long traffic tie-ups are common and commuters seek shortcuts with the zeal that early explorers reserved for the Northwest Passage.

"You've got to admit, it's a good political move for someone who represents this area," said Ben Candler, one of the more than 30 home-bound motorists who stopped at a McLean-area overlook to hear Wolf's traffic gospel. "Face it: We're suffering."

For Wolf, as for all Northern Virginia politicians, traffic jams are becoming an increasingly important issue. An estimated 533,000 Northern Virginians commute to work each day, and a recent study prepared for the General Assembly concluded that the region's traffic jams and travel times are likely to worsen in the 1980s.

Public opinion surveys in the region consistently have ranked traffic congestion among the area's most important issues, right up there with such familiar favorites as the economy and development. No bond issue in Fairfax County, the politicians there often note, was more popular last fall than one calling for better roads.

Conscious that Washington suburbanites vote with their wheels, Wolf and other area politicians have wasted no time in positioning themselves on the side of the commuter. "Transportation is the issue in Northern Virginia, and has been for 10 years," said Richard Leggitt, an aide to Rep. Stan Parris (R-Va.). ". . . We're just like Frank. We know which side our bread is buttered on."

Such reasoning is turning Northern Virginia politicians into vocal--and sometimes successful--lobbyists for the interests of their commuter-constituents. Some recent examples:

Wolf helped negotiate the opening of a two Rosslyn-area I-66 ramps to all traffic during rush hours, set a public hearing on I-66's car-pool restrictions for April 14 and won a Transportation Department agreement to open the Dulles Airport Access Highway to two-member car pools.

State Sen. Richard L. Saslaw (D-Fairfax) won the approval of Gov. Charles S. Robb and Virginia highway officials to experiment with opening the Shirley Highway's express lanes to three-member car pools.

State Sen. Charles J. Colgan (D-Prince William) tried and failed to get the state legislature to open those lanes on I-395 to handicapped drivers.

Nor has the action ended. Wolf is concentrating his energy on an effort to secure $6 million in federal funds to widen the George Washington Parkway between the Theodore Roosevelt Bridge and Spout Run--an idea that had fallen into oblivion since former Republican Rep. Joel Broyhill first suggested it in 1964. On Friday, Sens. John W. Warner and Paul S. Trible (R-Va.) announced they were joining Wolf's campaign and would introduce similar legislation in the Senate.

A host of politicians are agitating for a relaxation of the HOV-4 four-member car-pool restrictions on Shirley Highway and I-66, said to be the most stringent in the country, and the removal of a planned, $22.9 million computerized traffic-control system for those roads.

Wolf, who surveys the traffic situation daily while commuting in a 1981 Buick between his Fairfax County home near Reston and his Capitol Hill office, said his transportation-related activities are spurred not by political motives but by a desire to serve his constituents.

"I think it's my duty to look into this," he said gravely. "I believe very deeply in this, and I believe I can make a difference."

Still, there is little question that the second-term congressman is likely to pick up support from voters who travel the clogged highways. The Dulles Airport Access Highway agreement, for example, is certain to be popular among Reston area residents, whose cars turn Rte. 7 into a virtual parking lot during the morning rush hour.

"It was the talk of the bus," said one area resident the day after Wolf's announcement. Reston, coincidentally, has been one of the most Democratic areas in his district.