Kennedy, the ex-wife of New York Gov. Andrew Cuomo, Robert F. Kennedy's daughter and the niece of the late President John F. Kennedy, went on trial Monday in suburban New York.
In his opening statement, defense lawyer Gerald Lefcourt told the six jurors that Kennedy was not disputing that she drove erratically. Rather, he says, Kennedy accidentally took a sleeping pill that morning instead of her thyroid medication.
Blood tests revealed a small amount of the sleeping drug zolpidem.
Prosecutor Doreen Lloyd said even if the pill were taken accidentally, Kennedy violated the law "by failing to stop and pull over as she felt the onset of symptoms."
Lefcourt said Kennedy never knew what the drug was doing to her. He said the medication "hijacks your ability to make decisions."
Kennedy was arrested in 2012 after her car hit a tractor-trailer on an interstate highway near her home outside New York City. She drove to the next exit, where she failed a sobriety test, police said.
A fellow motorist, William Carlino, testified Monday that he found Kennedy slumped over the wheel and disoriented. Carlino said her car had one wheel without a tire.
Another witness, Henry Myers, said he saw Kennedy swerve her car into the tractor-trailer and keep driving despite damaging her tire.
Ethel Kennedy was among the supporters at her daughter's trial; Robert F. Kennedy's widow walked slowly with an escort as she entered the courthouse. Robert Kennedy Jr. and Douglas Kennedy also were in the courtroom.
The case was being heard in state Supreme Court, a rarity for such a minor charge, but Kennedy's lawyers successfully argued that the Town Court in Armonk, which had jurisdiction, was too small and poorly equipped for the trial.
A town judge and a state judge both refused defense efforts to get the charge dismissed, despite warm letters from family and friends extolling Kennedy's work in human rights around the world.
Kennedy, 54, of Bedford, won permission from Justice Robert Neary to miss last week's jury selection because she was on a human rights trip to Western Sahara.
Because the alleged offense is a misdemeanor, there are just six jurors. The trial is expected to last about a week.
Douglas Kennedy took another minor criminal case to trial in 2012. He was acquitted in a nonjury case of child endangerment and harassment charges stemming from a scuffle in a hospital maternity ward in Mount Kisco.