Kerry Kennedy was acquitted Friday of charges of driving under the influence of drugs.

Kennedy had insisted she took Ambien by accident that night. She swerved into a tractor-trailer on an highway in Westchester in July 2012, and prosecutors argued she should have pulled over immediately when she realized something was wrong. In the four-day trial, her defense attorneys argued that she never realized she was impaired until after the crash.

The six-person jury's decision was unanimous.

Kennedy is the daughter of the late Sen. Robert F. Kennedy and the former wife of Gov. Andrew Cuomo. Her lawyers also argued that she wouldn't have been charged with a misdemeanor if she had not been a Kennedy, since most cases of driving under the influence of alcohol or drugs are settled with a noncriminal violation.

Written with wire reports