People are dying on the nation's highways at a record low rate, and a crackdown on drunken drivers and increased use of seat belts deserve much of the credit, the U.S. Department of Transportation says.

The highway death rate dropped to 2.1 people per 100 million miles driven in 1990, the department said Wednesday. The actual number of fatalities also declined to 44,500 from 45,550 in 1989, according to transportation department projections.The projected total represents a continuing significant improvement over the 1966-1980 period, when the annual death toll often totaled more than 50,000.

Transportation Secretary Samuel K. Skinner attributed the improvement in large part to campaigns against drunken driving and the sharply increased use of automobile safety belts.

"While the number of traffic deaths is still too high, the reduction in fatalities is impressive because of an increase in the number of drivers and vehicles on the highways," Skinner said.

Jerry Ralph Curry, head of the National Highway Traffic Safety Administration, said the drop in the fatality rate is especially significant.

"Had the 1980 death rate of 3.3 deaths per hundred million miles remained constant, 151,000 more people would have died in traffic crashes from 1981 through the end of 1990," Curry said.

Alcohol-related highway deaths in 1990 are projected to be 11 percent below the benchmark year of 1982, Curry said.