WHITE PLAINS - A toxicologist testified today in the drugged-driving case involving Kerry Kennedy.

On July 13, 2012, Kennedy was arrested in Armonk after she sideswiped a tractor-trailer on Interstate 684.  She is facing one misdemeanor count of driving while ability impaired.  
The main witness for the prosecution Tuesday was Elizabeth Spratt, the head toxicologist at the Westchester County Department of Labs.

Spratt testified about tests her office conducted on urine and blood samples from Kennedy, as well as the effects of Ambien.

Under cross-examination, Spratt admitted she had no way of knowing what effect Ambien had on Kennedy's ability to drive.

Spratt did say people on Ambien can experience amnesia while on the drug, but said Kennedy should have been aware the drug was taking effect.

Kennedy's defense said that she confused her Ambien with another medication.

If it is ruled that Kennedy did not know what was happening, the jury could acquit her.

Kennedy is expected to testify when the defense begins presenting its case.