Police officers commonly use three field sobriety tests are conducted in the state that has been standardized by the National Highway Traffic Safety Administration (NHTSA):
Horizontal Gaze Nystagmus (HGN) — Also known as the “ DUI eye test,” the arresting officer observes how the driver’s eyes react to external stimuli (e.g. following a flashlight or pen) to detect involuntary jerking movements (nystagmus) of the eyeball.
Walk and Turn — The driver is instructed to walk nine steps heel to toe along a straight line, turn and repeat.
Leg Stand Test — The driver is instructed to stand on one leg and remain in that position for thirty seconds to determine if his or her balance has been affected due to impairment. Read more about walking and standing DUI tests.
Post Arrest Tests —These are tests law enforcement officials may administer after you have been arrested. Read more about post-arrest DUI tests.
Additionally, officers often ask drivers to undergo other, nonstandardized field sobriety tests. Such tests have not been validated by the NHTSA or other authorities and may therefore not be indicative of impairment. The standardized tests have been analyzed, however, to suggest that there is a correlation between drug or alcohol impairment and an individual’s ability to drive.
The attorneys at Banks, Stubbs & McFarland LLP are keenly aware that the standardized field sobriety tests are highly subjective. Such tests are based on the observations of the arresting officer, and not everyone is a good candidate for each test.
With the HGN test, for example, some individuals may have certain eye or health conditions that police frequently mistake as signs of impairment. Similarly, the walk and turn test may yield inaccurate results, particularly for those who may be injured, overweight or elderly.
Finally, the fact that such tests are “standardized” means that they must be administered according to strict guidelines. Any deviation from those guidelines may invalidate the test results. At the end of the day, it takes an experienced Georgia DUI attorney to challenge the results of a field sobriety test.