The wife of Robert F. Kennedy Jr was charged with drunken driving after a police officer claimed he saw her run over a kerb outside a suburban school.
Mary Richardson Kennedy, (50) was arrested on Saturday with a blood-alcohol level of 0.11pc, Sgt Matt Dunn said. The US legal limit is 0.08pc.
Kennedy told police she was at the school in Bedford, about 45 miles (72km) north of New York, to pick up people from a carnival, authorities said.
Officers had visited the Kennedy home twice in the last week, on May 10 and May 13, but Lt Jeff Dickan said those visits were unrelated to the arrest.
In one call, Kennedy reported a dispute between children, Dickan said.
The other visit resulted in a state domestic incident report, but there were "no crimes committed, no report of assault, no arrests and no need for follow-up," Dickan said. He declined to elaborate.
Police would not say whether anyone else was in the car when Kennedy was arrested or if she had a lawyer.
Environmental attorney Robert Kennedy Jr is the son of former Senator Robert Kennedy and nephew of President John F. Kennedy.
Meanwhile, Robert De Niro was among the stars who recalled their friendship with the Kennedy family.
"There's a long history," said De Niro, choking back tears hours before he was to help the Boston Pops perform the world premiere of a musical tribute to President John F. Kennedy and Senators Robert and Edward Kennedy.
"I get emotional ... about the whole family," De Niro said.
Morgan Freeman, Ed Harris and Cherry Jones joined De Niro as celebrity narrators for The Dream Lives On: A Portrait of the Kennedy Brothers, at Boston's Symphony Hall.
Composer Peter Boyer and lyricist Lynn Ahrens wrote the piece, which will be performed several other times this season as a centrepiece of the orchestra's 125th anniversary season.
Excerpts of some of the brothers' most iconic speeches are intertwined with music and video during the multimedia presentation.