Former Tisbury selectman A. Kirk Briggs was convicted of drunk driving and vehicular homicide yesterday in Edgartown District Court and sentenced to 21 months in the Dukes County jail.

As part of a plea bargain, Mr. Briggs changed his previous not guilty plea and avoided a mandatory two-and-a-half-year jail term that would have allowed him no chance of parole.

Under yesterday's deal, Mr. Briggs will be eligible for parole after serving half the sentence, or ten and a half months. Mr. Briggs is 55.

Almost nine months ago, just before midnight on August 28, Mr. Briggs was driving his 1989 Chevy pickup truck down New York avenue toward Vineyard Haven, when his truck hit a 25-year-old woman who was walking her bicycle along the roadside.

The woman, Jelena Shvaikovskaja, died the next day at a Boston hospital. A music student from Estonia, she had come to the Island for the summer and was working two jobs, one at Cronig's in Vineyard Haven, the other at Mad Martha's in Oak Bluffs.

According to police reports, Mr. Briggs failed field sobriety tests and later consented to a breathalyzer test at the jail, where his blood alcohol level registered .14. The legal limit is .08.

Mr. Briggs did not speak in court yesterday other than to answer simple yes or no questions posed by district court Judge Joseph Macy. But his defense attorney, Charles Morano, told the judge that Mr. Briggs had written a "poignant letter" to the victim's family that expressed his remorse.

But Judge Macy offered a stern reply. "You can be as sorry as you want, but this conduct is inexcusable," he said. The judge also recommended that Mr. Morano submit the letter to the district attorney and not the victim's family, adding, "The family may never want to hear from you again."

None of Miss Shvaikovskaja's family came to court yesterday. Her father lives in the Boston area but decided not to come to the Island.

"It was the decision of the family not to attend because it would be too emotional for them," said Cape and Islands assistant district attorney Lisa Edmonds.

The judge asked if there was anything else the victim's family wanted the court to hear. "Given my conversations with her family and the many letters from professors, she was a girl with her whole life in front of her."

Mr. Morano asked the judge to consider Mr. Briggs's character, submitting letters on his behalf and reminding the court of Mr. Briggs's service in the Navy, his terms on the board of selectmen and the Martha's Vineyard Commission and his years as a youth sports coach.

"He is a father and has children around the same age as the victim," said Mr. Morano.

For much of the morning, Mr. Briggs waited, sitting on a front row bench in the courtroom flanked by his family - his daughter, his two sons and his wife, who wiped tears from her eyes and often rested her head on her husband's shoulder.

Friends of the Briggs family - 10 in all - filled two of the center benches in the courtroom. They stayed the whole morning and until 12:15 p.m. when Mr. Briggs finally stood and listened as his lawyer entered a guilty plea. Mr. Briggs, who wore dark slacks and a cream-colored sportcoat, then listened as Ms. Edmonds, the prosecutor, recounted the events of the night of August 28 and the following day.

The procedure lasted just 15 minutes, and when it ended, Mr. Briggs was led to a front part of the courtroom called the dock where a court officer asked Mr. Briggs to face the wall and then put shackles on his ankles.

"Obviously Mr. Briggs did not set out to hurt anyone, but it was an intentional act, drinking and then getting behind the wheel," Ms. Edmonds, said later. "He's hurt his family, the community and devastated Jelena's family for the rest of their lives. All over a couple drinks. Hopefully, people will learn from this."

In addition to the jail term, Mr. Briggs will be on probation for three years after his release. He will also be required to log 100 hours of community service.

And even as Mr. Briggs begins the first day of his jail sentence, he may soon find himself in court again, facing a wrongful death lawsuit filed in January in Norfolk Superior Court by the Shvaikovskaja family.