Transportation Secretary Neil Goldschmidt said yesterday that the United States must improve its rail and road access to major ports during the 1980s if it is to meet its potential for expanding foreign commerce and reducing trade deficits.

"Without prompt action, we may not have the system we need" to support the flow of commerce needed to expand exports, Goldschmidt said in a speech to the Washington Press club.

He announced two initiatives to deal with the port problem. In the future, he said, regional transportation planning "must include a component which addresses goods movement, and specifically the link between rail and highways, particularly in port communities." Transportation planning today looks primarily at the movement of people, he said.

Second, he said, the Transportation and Commerce departments will do a joint study on ground transportation service in port cities.

Goldschmidt said these measures are necessary because land transportation systems have not kept pace with improvements in port technology, such as containerization.

As one example, he cited the new Dundalk Marine Container Terminal in Baltimore, next to Interstate 695. However, he said, "there is no exit ramp for vehicles coming from the north or east. The result is a routing that is longer, slower, more congested and ends up costing more, as well."

"Next to decreasing our reliance on imported oil," Goldschmidt said, "improving our nation's performance in world trade is the surest path I know to achieve our goals of stabilizing the dollar and increasing job opportunities. . . ."

In other matters, Goldschmidt said the transit aid section of the proposed windfall profits tax would contain money for starting rail or bus systems in cities that don't have them. Earlier versions of the proposal had no "new starts."

However, Goldschmidt siad in an interview, such programs would have to be carefully selected.

"We don't want to buy a train," he said, "we want to buy a strategy. If there is a 10-year plan that makes sense we will buy it."

He said that the purchase of right-of-way for transit tracks will be a possible use of windfall tax money. Right-of-way purchase is a favorite technique of highway builders. Such advance planning can determine land-use patterns for decades to come.