A niece of assassinated US president John F. Kennedy was acquitted of drugged driving by a six-member jury on Friday, closing a trial that has captivated the tabloid press.
Kerry Kennedy gave herself a round of applause after the verdict was read out in a New York county court, media reported, where she was joined by her mother Ethel and other supporters.
"She was found not guilty," a court official confirmed to AFP.
The jurors took around an hour to reach their verdict. According to US media, she faced up to a year in jail if convicted.
Kennedy took a sleeping pill before setting off on an erratic five-mile drive in her luxury SUV in July 2012.
She sideswiped a tractor-trailer on a highway in Westchester County before being found slumped behind the wheel.
Kennedy, 54, argued that she took the pill by accident, mistaking it for her morning thyroid medication.
Prosecutors argued that as a veteran user of sleeping pill Ambien she must have felt the effects of the pill before passing out -- and broke the law by failing to stop driving.
To find Kennedy guilty, jurors had to determine that she realized she was drugged and decided to stay on the road.
Kennedy is the former wife of New York state governor Andrew Cuomo and a daughter of assassinated senator Robert Kennedy.