To determine an individual’s sobriety, highway officers use what is known as the Standardized Field Sobriety Test (SFST). The SFST is a combination of three exams conducted and judged by police officers in a uniform method to secure evidence of an individual’s potential intoxication or impairment and to gain “probable cause” for an arrest. The three exams are the Horizontal Gaze Nystagmus (HGN), the Walk-and-Turn (WAT) and the One-Leg Stand (OLS).
Horizontal Gaze Nystagmus
Nystagmus is the spontaneous jerk of the eye that happens inherently as the eyes move from side to side. When a person is intoxicated by alcohol (and numerous drugs and controlled substances), this movement is typically exaggerated. An officer will test for this by asking a suspect to follow an object with their eyes as it moves across his or her field of vision.
Walk & Turn
For this test, a person is told to take nine steps, toe to heel, in a straight line. After completion of those steps, the individual is asked to pivot on a single foot and walk back to the point of origin in the same fashion. Officers judge impairment based on factors including:
- Lack of attention;
- Failure to maintain balance; and
- Failure to follow physical instructions in an exact or satisfactory manner.
One Leg Stand
In this component of the SFST, the suspect is asked to stand on one foot (with the other about six inches from the floor) and count by thousands (one thousand one, one thousand two, etc.) until instructed to stop by the officer. This test is typically administered for around 30 seconds, and officers may judge based on physical mistakes or counting errors.
Of course, there are many personal conditions that do not involve impairment that may inhibit a person’s ability to perform these tests. For experienced DUI representation in Colorado Springs, contact the Colorado drunk driving lawyers with the Bussey Law Firm, P.C. at (719) 475-2555 for a free case review.