It has been 16 years since the Silver Bridge collapsed into the Ohio River near Point Pleasant, W.Va., killing 46 people caught in their cars but spawning legislation that required federal standards for bridge inspection.

Like most federal highway standards, however, enforcement rests with the states. The Federal Highway Administration has only oversight responsibility and its only leverage on the states is the threat of withholding federal highway funds -- a big stick in theory, but politically impossible in reality.

Last week, National Transportation Safety Board Chairman Jim Burnett held hearings in Atlanta following the April 24 collapse of a bridge over Chickasawbogue Creek, two miles north of Mobile, Ala., on U.S. 43. Only one car was on the bridge at the time of the early afternoon collapse and the driver escaped, but the bridge carried 20,000 vehicles a day.

The structural steel holding up the bridge had been resting in the water since the bridge was built in 1958. The federal standard calls for bridge inspections every five years, but testimony at the hearing indicated that there had probably never been any kind of inspection and certainly never an underwater inspection.

Burnett said, "My fear is that the problem of corrosion of exposed steel bridge supports is of undefined proportions. If that is so, then the potential for a disastrous accident is likewise unknown."

ROOM AT THE TOP . . . Meanwhile, the safety board continues to function without its full complement of members. Burnett, Vice Chairman Patricia Goldman and G.H. Patrick Bursley have been holding down the fort, but Bursley's term has expired. And he is to leave when his replacement arrives. That makes a total of three vacancies and two vacant seats. Board meetings for today and Aug. 6 have been cancelled for lack of a three-member quorum.

Vernon Grose, who served for nine months on a recess appointment without benefit of Senate confirmation, was renominated but is still awaiting a confirmation hearing. The Senate Commerce Committee has told the White House that it won't consider Grose until three nominations have been sent to Capitol Hill. Two other names are reportedly on their way: John Lauber, director for human performance at the National Aeronautics and Space Administration, and Kenneth John Hill, who served on the staff of former White House deputy chief of staff Michael K. Deaver.

Meanwhile, Burnett has appointed John Arthur Hammerschmidt as his special assistant. He is the son of Rep. John Paul Hammerschmidt (R-Ark.), the ranking Republican on the House Public Works and Transportation subcommittee on aviation, which oversees the board. Burnett, a former Arkansas judge, once worked in Hammerschmidt's congressional office.

OFF THE GROUND. . . Get ready for the Railroad Accounting Principles Board. This agency, authorized by the railroad deregulation legislation of 1980, received an appropriation and started hiring in January. It has about 10 of 13 projected employes.

The board is headed by Charles A. Bowsher, the comptroller general, and has six other part-time members. Its exact duties are undefined, although comments have been received in response to a Federal Register notice. It is supposed to establish cost-accounting principles for rail carriers, subject to the jurisdiction of the Interstate Commerce Commission.

DEER-EGULATION? . . . Sunday a New York Air jetliner struck and killed two deer on a Dulles Airport runway. Yesterday, this exchange occurred in the Federal Aviation Administration building, where the safety board is a tenant.

"Pretty good venison in the FAA cafeteria," said the safety board.

"What do want us to do?" asked the FAA. "Pass a regulation forbidding deer from jumping the fence?"