Field Sobriety Tests

The One Leg Stand Test | What Drivers Should Know About SFST

June 3, 2026 | by Danny Glover

The One Leg Stand, or “OLS,” is one of three “verified” Standardized Field Sobriety Tests (SFSTs) recognized by the National Highway Traffic Safety Administration (NHTSA), alongside the Horizontal Gaze Nystagmus and the Walk-and-Turn test. If pulled over on suspicion of impaired driving on the Outer Banks of North Carolina, there’s a reasonable chance the charging officer requested the suspect to submit to the One Leg Stand test.

The One-Leg Stand is a type of divided-attention test. The officer instructs a driver to stand on one leg, raise the other approximately six inches off the ground, keep the raised leg straight, point the toe of the raised foot, and count aloud until told to stop. Training materials direct the investigating officer to time the driver for 30 seconds. That sounds relatively straightforward. Like other field sobriety tests, however, the administration, interpretation, and reliability of the One Leg Stand can be far more complicated than the basic instructions suggest.

Whether the One Leg Stand is actually a reliable indicator of impairment depends on officer training, adherence to proper procedures and protocols, roadside conditions, and the individual being tested. SFST results are regularly used as evidence in DWI prosecutions. They support arrest decisions and the determination of probable cause to arrest. They get presented to judges and juries. In North Carolina, courts apply N.C.G.S. § 20-138.1 to evaluate impaired driving charges, and the use of OLS evidence in that process can make or break a case.

The DUI Eye Test (HGN) | What It Measures and How Reliable It Really Is

May 16, 2026 | by Danny Glover

The “DUI eye test” refers to the Horizontal Gaze Nystagmus, or “HGN.” It is one of the three “verified” Standardized Field Sobriety Tests (SFSTs) recognized by the National Highway Traffic Safety Administration (NHTSA), along with the walk-and-turn and the one-leg stand.

HGN is a “sobriety test” where an officer holds a stimulus, usually a pen, a fingertip, or a small flashlight, in front of the suspect’s face and asks the driver to follow it with their eyes without moving their head. The officer is watching for an involuntary jerking or twitching of the eyes. Some officers describe it as looking like windshield wipers going back and forth on a dry windshield. That jerking motion is referred to as a nystagmus and it is purportedly an indicator of appreciable impairment by alcohol and possibly other substances.

The test sounds simple. The science behind it is not. Whether HGN is actually a reliable indicator of impairment in any given case is a separate question. Even when scientifically reliable, the accuracy and reliability of field sobriety testing largely depend on the training, experience, and objectivity of the charging officer. That matters when the test results are summarized in a police report, described on the witness stand, or used to support probable cause for arrest under North Carolina’s impaired driving statute, N.C.G.S. § 20-138.1.

Standardized Field Sobriety Tests and DUI Charges in North Carolina

March 24, 2023 | by Danny Glover

In North Carolina, driving under the influence (DUI) charges are taken very seriously. If you are pulled over on suspicion of driving under the influence (driving while impaired), the officer may ask you to perform a standardized field sobriety test (SFST).

Field Sobriety Tests (FST) or Standardized Field Sobriety Tests (SFSTs) are designed to help determine whether you are impaired.

In this blog post, we will discuss the SFSTs and DUI charges in North Carolina, including what you should know if you are facing an allegation of “drunk driving.”