Kevin N. Cooper, 26, the Glen Burnie, Md., man who was convicted of manslaughter and drunken driving in an auto accident last Christmas Eve that killed five members of a Montgomery County family, was sentenced yesterday to three years in jail with all but six months suspended.

Cooper, a carpenter, was ordered to serve the six months in a work-release program that will permit him to leave jail on weekdays if he gets a job. The prison sentence plus five years of probation and the requirement that Cooper perform 500 hours of community service were imposed by Carroll County Circuit Judge Donald Gilmore.

The judge noted that Cooper is not a hardened criminal, according to a prosecutor present at the sentencing.

Cooper could have been sentenced to up to 15 years in jail--three for each of five counts of manslaughter.

Gilmore's sentencing action was promptly criticized by antidrunk-driving groups.

"It's outrageous. . . a giant step backwards," said Thomas Sexton, who, along with his wife Dottie, are state representatives for the Maryland Chapter of Mothers Against Drunk Driving (MADD).

"After two years of trying to do something in the state, it appears that the judicial system has not gotten the message," Sexton said, adding that 16 pieces of legislation against drunk driving have been passed in the Maryland in that period.

Cooper was convicted of five counts of auto manslaughter and drunken driving.

On a road near Mount Airy in Frederick County, Cooper's car had swerved into the wrong lane and slammed into a car driven by Martha Proctor, 45, of Clarksburg. Two of Proctor's sons and three of her grandchildren were killed.

Cooper had testified that he drank seven beers at an office Christmas party before the collision, but felt sober and capable of driving. Evidence showed that Cooper's blood alcohol level was .12 about 90 minutes after the accident and the state's chief toxicologist testified that his blood alcohol level was probably between .13 and .14 when the crash occurred. Under Maryland law, a person is legally intoxicated when the level reaches .13.

The trial was held in Talbot County because of pretrial publicity and sentencing was in Easton.

After the sentencing, Tonya Jeanette, 22, one of the Proctor children who survived the crash, said she was confused, "disappointed" and "not satisfied at all," with the judge's decision.