Police officers in South Carolina and other states are increasingly targeting alleged drunk drivers that they deem “hardcore” — those who have been through the DUI system on numerous occasions. Authorities argue that those particular defendants have already mastered the standardized field sobriety test so that they can perform it while intoxicated, which is why they advocate for the horizontal gaze nystagmus test. That evaluation, also known as the horizontal gaze test, evaluates a driver’s sobriety by observing the behavior of his or her eyes while looking side-to-side.
There are issues, of course, with the horizontal gaze test. Attorneys and judges both agree that the gaze test is unlikely to be admissible in court, even though evidence suggests that it is more effective at identifying intoxicated drivers with BAC levels between 0.8 and 0.12 percent. Although this test has long been considered subjective and inadmissible in court, more prosecutors are pushing for its use and attempting to lay proper groundwork for its ongoing implementation.
When officers conduct the horizontal gaze test, they are looking for jumpy eye movement that occurs when the driver is attempting to follow a moving object such as a pen. The officer stands about an arm’s length away to administer the test. Authorities argue that it is a particularly valuable tool because the defendant cannot achieve success against the test through practice — our bodies cause the jumpy eye movements because of the effects of alcohol, no matter how we try to control the effect.
Even though authorities are pushing for increased admission of the horizontal gaze test in court, it is still considered subjective and therefore largely unreliable. Further, if a driver is not subject to a properly administered evaluation, an improper field sobriety test can be thrown out of court entirely, leaving little evidence for the prosecution. Even if you have failed a standardized field sobriety test or horizontal gaze nystagmus test, you are not automatically considered guilty of DUI; an attorney can help you understand your options.
Source: American Prosecutors Research Institute, “Admissibility of Horizontal Gaze Nystagmus Evidence,” accessed Sep. 09, 2015