The horizontal gaze nystagmus test (HGNT) is one component of field sobriety testing conducted by police officers to determine whether a suspect is intoxicated. The HGNT is the centerpiece of the National Highway Traffic and Safety Administration's (NHTSA) Standardized Field Sobriety Tests. The walk-and-turn test and the one-leg-stand test are also included in this three-test battery of field sobriety tests.
Prior to the NHTSA funded work at standardizing field sobriety testing, roadside tests were selected and administered according to personal preferences. Today, however, many police agencies and officers use the standardized three-test battery that resulted from NHTSA's work. Although the HGNT is used in conjunction with the walk-and-turn and the one-leg-stand tests, this discussion will focus solely on the HGNT due to the recent decision by the North Dakota Supreme Court in City of Fargo v. McLaughlin.
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