Kennedy "cut a wide swath of danger and risk" when she was arrested in July after her Lexus swerved into a tractor-trailer near her home north of New York City, Justice Elyse Lazansky wrote in a ruling filed in North Castle Town Court.
The judge acknowledged Kennedy's public service but said a trial didn't have to end that.
"It is safe to say that Kerry Kennedy is not a typical criminal defendant. She has achieved a great deal and is dedicated to good works . . . other gifted powerful and wealthy politicians and celebrities too numerous to mention have faced a wide variety of criminal charges and have gone on to do their jobs or serve the public in many important ways," Lazansky said.
No trial date was set, but a trial would be in October at the earliest.
When asked how Kennedy felt about the decision, defense attorney Gerald Lefcourt said Kennedy was "not happy about it, but it is what it is."
"We are very disappointed and we disagree with it, but we have every confidence that Ms. Kennedy will be exonerated," Lefcourt said.
Police said the daughter of the late Sen. Robert F. Kennedy failed sobriety tests. A small amount of a sleeping drug was found in her blood. She said she thought she accidentally took a sleeping pill that morning instead of thyroid medication.
Prosecutors had argued that dropping the charge would feed the perception that famous people are treated differently.
Kennedy and her lawyers had argued in court papers that fairness demanded a dismissal. They said she took the sleeping pill accidentally and the only harm done was to Kennedy's own pride and name. They recounted her work for social justice and included many glowing letters from friends and relatives.