A Standardized Field Sobriety Test (SFST) is a series of tests used by law enforcement to determine whether a driver is impaired by alcohol or drugs. The SFST consists of three parts: the horizontal gaze nystagmus, the one-leg stand, and the walk-and-turn. The SFST is considered to be more accurate than the PBT, and the results can be used as evidence in court in New Jersey.