The jury deliberated for about 45 minutes, hearing a brief readback of expert testimony, before breaking for the day. Deliberations in the drugged-driving trial resume Friday.
In closing arguments, the prosecution disputed Kennedy's claim that she never realized she was impaired after taking the sleeping pill instead of her daily thyroid pill.
Prosecutor Doreen Lloyd acknowledged that Kennedy took the sleeping pill by accident but said, "She is responsible for the chain of events that happened after that."
Lloyd insisted that the sleeping drug zolpidem works gradually, and Kennedy's testimony "belies the science of this drug."
She suggested Kennedy ignored the onset of symptoms because "she had a schedule to meet." Mocking the title of one of Kennedy's own books, she urged the jury to "speak truth to power."
Defense attorney Gerald Lefcourt countered: "Accidents are not crimes."
He said there was no evidence - and it made no sense to believe - that Kennedy "operated her vehicle while she was aware she had ingested zolpidem, and when she became aware she continued to drive."
Kennedy, the daughter of Robert F. Kennedy and ex-wife of New York Gov. Andrew Cuomo, was arrested on a charge of driving while ability impaired following the 2012 accident. She could face up to a year in jail if convicted, although that would be unlikely for a first-time offender.
With Kennedy's mother, Ethel, and other relatives in the front row, Lefcourt said Kennedy was "not seeking advantage because of her family." He said the trial is "not a TV call-in program. This is an American court."
Earlier Thursday, Lefcourt introduced a medical journal article in support of Kennedy's testimony that she didn't realize while driving that she had accidentally taken the pill.
Data showed that people taking the sleeping pill zolpidem "frequently do not recognize their impaired state," the New England Journal of Medicine article from August 2013 said.
Lloyd countered that the article was about impairment the morning after getting a night's sleep, not about impairment before sleeping.
Kennedy testified Wednesday that she didn't remember anything that happened as she drove on I-684 one summer day in 2012 - swerving out of her lane, hitting the tractor-trailer and blowing a tire.
And she said she never sensed that the drug was having an effect.
"If I realized I was impaired, I would have pulled over," Kennedy said Wednesday at her trial in White Plains.
The conclusion of the article on zolpidem was read from the witness stand Thursday by Dr. David Benjamin, a clinical pharmacologist who said he was involved in the testing of zolpidem as the manufacturer sought FDA approval in the 1990s.
He said it would be even more difficult for someone who didn't know they had taken the drug "to understand what was going on."
On cross examination, Benjamin said "a reasonable person" would check a prescription bottle before taking the drug. But when prosecutor Doreen Lloyd asked him to say it was Kennedy's fault, the defense objected and the judge sustained the objection.