Kennedy pleaded not guilty Tuesday night in North Castle Town Court to a charge of driving while drug-impaired. She was released but must submit to fingerprinting by state police and to evaluation by a substance abuse agency. She is due back in court Aug. 14.
Kennedy, 52, was arrested Friday after state police said her Lexus struck a tractor-trailer on Interstate 684 north of New York City. Police said she then took an exit off the highway before her car became disabled.
A police report released Tuesday said Kennedy failed several sobriety tests and was swaying and slurring her speech.
Kennedy said she remembers getting on the highway to go to the gym "and then I have no memory until I was stopped at a traffic light and a police officer was at my car door."
She said she felt "confused and erratic" and told the officer she might have accidentally taken an Ambien sleeping pill instead of her daily thyroid pill. But drug tests later that day showed "no alcohol, recreational drugs or prescription medication in my system," she said.
Tests on blood and urine that the court will rely on have not yet been completed, Town Justice Elyse Lazansky said.
Kennedy, daughter of Sen. Robert F. Kennedy and niece of President John F. Kennedy, said she then underwent neurological tests in Manhattan. An MRI revealed "an area of hyper density" in her brain that apparently resulted from a head injury she said she suffered some time ago, she said.
She said the tests led doctors to believe "that this accident was caused not by a sleeping aid but by a complex partial seizure."
Kennedy said she would continue to receive treatment for the condition and should be able to live "symptom-free."
She apologized to the driver of the tractor-trailer she hit and other drivers on the road Friday morning.
It has been a difficult year for Kennedy family members in the New York suburbs. Kennedy's close friend and sister-in-law, Mary Kennedy, hanged herself at home in May. Her brother Douglas Kennedy is fighting charges stemming from his attempt to take his newborn son from a maternity ward.
Kerry Kennedy and Andrew Cuomo married in 1990, joining two of America's most prominent political families. They split in 2003 in a messy public divorce that played out in the tabloids. They have three daughters.