Big trucks with double trailers are expected soon to start traveling along major highways in the Washington region under new federal rules that prompted complaints and confusion yesterday among Maryland and Virginia officials.

Virginia previously banned the twin-trailer trucks. Maryland allowed them only on Interstate highways. The District allows trucking firms to apply for permits to bring dual-trailer vehicles into the city, but a D.C. official said yesterday that no trucker ever sought one.

These state and city regulations, along with similar rules imposed by other states chiefly on the East Coast, have been set aside under a provision included in the Surface Transportation Assistance Act of 1982, which was aimed mainly at increasing the federal tax on gasoline by a nickel a gallon.

"It's kind of obvious that they weren't doing any real homework on the issue," said John Bertak, a Maryland Transportation Department spokesman, complaining that some of the highways chosen by federal officials would be dangerous for large trucks.

The federal rules also will allow wider and longer single-trailer trucks on some major highways than Virginia, Maryland and the District previously permitted. When bigger trucks will start showing up on Washington-area highways was unclear.

The Federal Highway Administration's new truck rules were scheduled to go into effect yesterday. Maryland officials said, however, that the state plans to continue enforcing its tighter truck limits until a new state law patterned on the federal standards goes into effect, probably June 1.

Virginia officials, after initially refusing to enforce the new law, later reversed themselves and said they would immediately abide by the new federal policies. The District also will permit the bigger trucks on two main routes, officials said.

A spokesman for Consolidated Freightways, one of the nation's largest long-distance trucking firms, said yesterday that twin-trailer trucks would start traveling through Virginia and other states where they were previously prohibited as soon as the states adopted the new federal limits.

Consolidated spokesman Ray Kershner said the big trucks will help reduce shipping costs for consumers and rejected complaints by opponents of the dual-trailer vehicles who argue that they are unsafe.

In Virginia, state officials selected about 155 miles of noninterstate roads for the trucks, but federal officials picked another 1,760 miles.