At the first regional conference yesterday on the trouble-plagued Capital Beltway, Virginia and Maryland state officials spoke eloquently of their desire to cooperate in seeking solutions to congestion and safety problems on the 66-mile circuit shared by the two states. But on specific long-term proposals, early disagreements became apparent.

In the initial stages of discussion about a new Washington area bypass to relieve the Beltway, Virginia officials seem adamant for a "Northern Potomac crossing" that would extend from Leesburg, Va., to Rte. 70 near Frederick, Md., while Maryland officials seem equally convinced that a "Southern Potomac crossing" from Baltimore to Fredericksburg, Va., is the best solution.

"This morning I met with Maryland Gov. Harry Hughes and I pledged my constant cooperation and negotiation, but I will not equivocate on the intentions of Virginia," said Virginia Gov. Gerald L. Baliles in his lunchtime speech to the gathering of about 250 transportation planners, state and local officials, and business leaders in Greenbelt.

"We must proceed on the planning and construction of the Outer Beltway," Baliles said. " . . . The logic of a Washington bypass running west of the city is obvious on the face of it and compelling. As much as one-third of the Capital Beltway's traffic could be diverted away."

Baliles also called for improved access to Dulles International Airport "via Metro."

The conference, entitled "Solving the Problem of Greater Washington's Main Street," was a joint effort of the Greater Washington Board of Trade and the Metropolitan Washington Council of Governments.

For the most part, the conference was a rousing show of unity, with everyone agreeing that there is no greater or more urgent problem in the metropolitan area than the crowded and dangerous conditions on the Beltway. Last year, more than 2,300 accidents were reported on the route, with 18 percent involving tractor-trailers. At rush hour, commuters now travel at speeds of only 15 to 20 mph on some parts of the Beltway; within 20 years, similar congestion is expected to spread to nearly half the route, according to a recent COG report.

Long-term solutions to Beltway congestion were only a part of the day-long conference. Capt. H.D. Northern of the Virginia State Police talked about truck inspection and enforcement. Capt. William H. Hurley, his counterpart with the Maryland State Police, discussed accident responses. Albert A. Grant, COG director of transportation, gave a picture of what the Beltway will be like in 2000. Short-term remedies such as increased ride-sharing programs and the installation of message signs to alert motorists to road conditions were also considered.

The effect was that of a giant work session, where the participants acknowledged and studied the problem and possible solutions while stopping short of making decisions.

"The issues surrounding the Capital Beltway are regional concerns," said Nancy Falck, a Fairfax County supervisor who is president of COG. "Today we are publicly acknowledging that the problems of congestion and safety exist, that we, as leaders of the regions, recognize them, and that we are willing to take action to do something about them."

Edwin I. Colodny, president of US Air and the chairman of the board of trade's transportation coordinating committee, pointed out that the Beltway problem is personal as well as regional.

"Probably most of you traveled on some portion of the Beltway to get here," he said. "And in planning your travel, I am sure that serious consideration had to be given to the question of how long it would take to travel during rush hour to get here. And then you, if you are like me, silently invoked the assistance of the Beltway gods in keeping an accident from your path."