When a New Jersey driver is pulled over for potential drunk driving, they may be asked to perform certain field sobriety tests. Unless the driver is disabled or cannot otherwise perform the common field sobriety tests, the main tests that a driver is most likely to encounter are the walk-and-turn test, the one-leg test and the HGN test.
The walk-and-turn and the one-leg test are both "divided attention" field sobriety tests. As such, drivers are required to listen to the instructions given by the police officer while performing the required movement, such as walking heel-to-toe or standing on one foot. For these two tests are being performed, officers look for certain indicators that are indicative of impairment. These indicators include the inability to follow instructions, failure to listening to instructions and balance checking. Research on behalf of the National Highway Traffic Safety Administration, or the NHTSA, indicates that approximately 68 percent of those who do not pass the walk-and-turn test and 65 percent of those who do not pass the one-leg test have a BAC of at least .10 percent.
HGN stands for horizontal gaze nystagmus, which is an involuntary jerk of the eye. Individuals who are impaired often cannot follow an object from side to side without moving their head. If the person's eyes cannot follow the object smoothly without jerking, they may be impaired. Research from the NHTSA indicates that approximately 77 percent of individuals who exhibit this involuntary jerking have a BAC above .10 percent.
A driver who was not under the influence of either alcohol or drugs may not pass certain field sobriety tests, especially if they have a physical impairment. Because all cases are unique, someone accused of drunk driving should seek legal advice to determine what criminal defense strategies may be appropriate to challenge the charges.
Source: National Highway Traffic Safety Administration, "The Highway Safety Desk Book", November 30, 2014