An announcement by a commissioner of motor vehicles seldom merits front-page treatment. Traffic accident rates, license fees and truck weights do not often startle the reader or provoke a change in public opinion. But out of Albany, New York the other day came some figures that should do both. The mandatory seat belt law that went into effect three months ago in New York is being hailed as the cause of a dramatic drop in traffic fatalities.

Commissioner John Passidomo revealed statistics for January, February and March of this year. Auto accidents caused the deaths of 184 passengers and drivers during this period. The figure for the same three months of last year was 252. That 27 percent decline in fatalities is credited to the seat belt law alone because other relevant statistics,ch as the number of accidents and pedestrian deaths, did not change significantly.

New York was the first state in the nation to enact a mandatory seat belt law, and within weeks, Gov. Mario Cuomo was able to produce anecdotal evidence of its success. A grateful mother wrote that her two sons, who had never worn seat belts before the law took effect, walked away from a serious accident only because they had buckled up in compliance with the new rule. Others who had been in accidents acknowledged that the law had been an incentive to use the restraining devices that had saved them from injury or death. From the new statistics, however, we know that those individual stories were not an aberration. Seat belt use in January was up from 16 percent to 69 percent -- though it has fallen slightly in succeeding months -- and the life-saving results can be calculated.

The U.S. Department of Transportation will issue regulations requiring air bags in new cars unless states with two-thirds of the nation's population pass mandatory seat belt laws by April 1, 1989. Eight states have already done so, but only the statutes in New York and New Jersey have gone into effect. The good news from Albany should encourage other jurisdictions to follow New York's example and save lives.