By Christopher Zoukis
The Georgia Supreme Court sent a message to prosecutors in an October 2, 2017 opinion: A police officer’s testimony as to a defendant’s performance on a horizontal gaze nystagmus (“HGN”) test cannot, by itself, establish a numeric blood alcohol content level.
The HGN test is one of several field sobriety tests used by police officers when they suspect that a driver is drunk. When properly administered, the test reveals up to six “clues” that indicate impairment. In the case before the Court, Mellecia Spencer exhibited four out of six clues and was arrested for driving under the influence.
At trial, the State presented the police officer’s testimony on the HGN test results. The officer testified that “four out of six clues generally indicates a blood alcohol level equal to or greater than a 0.8.” On the basis of this testimony, which was not accompanied by any evidence of the scientific basis for the officer’s conclusion, Spencer was convicted.
The Georgia Supreme Court began its analysis by noting that precedent in the State requires a trial court to determine “whether a scientific principle or technique is competent evidence in a criminal case” prior to admitting such evidence. In this case, the Court determined that this did not occur but noted that “[i]t is generally accepted that the HGN test ‘has reached a state of verifiable certainty in the scientific community and is admissible as a basis upon which an officer can determine that a driver was impaired by alcohol.’”
As such, had the officer testified that the results of Spencer’s HGN test indicated impairment, the result would have been upheld. “But,” the Court noted, “whether the HGN test may properly be used as evidence that a driver is impaired by alcohol is not the same question as whether the HGN test has been established as an indicator of either a specific number or a numeric range of blood alcohol content.” As the Court pointed out, “only a single number was presented to the jury, and that number established a numeric blood alcohol content exceeding the per se legal limit.” Thus, “these ‘linguistic gymnastics’ without satisfying the required evidentiary standard. This is improper. Before any such evidence may be admitted, the proponent must satisfy the requirements….”
Because no scientific or medical evidence was presented to establish the scientific validity of the officer’s correlation between the number of HGN clues and a specific blood alcohol content, the trial court abused its discretion in admitting his testimony into evidence. Consequently, the Supreme Court reversed Spenser’s conviction for DUI. See: Spencer v. State, 2017 Ga. LEXIS 828 (2017).
Originally published in Criminal Legal News on November 16, 2017.