Standardized Field Sobriety Tests

[av_layerslider id=’2′] [av_heading tag=’h2′ padding=’10’ heading=’Standardized Field Sobriety Testing’ color=” style=’blockquote modern-quote’ custom_font=” size=” subheading_active=’subheading_below’ subheading_size=’15’ custom_class=”] Standardized Field Sobriety Tests Developed by the National Highway Traffic Safety Administration (NHTSA)
[/av_heading] [av_textblock ]

Standardized Field Sobriety Testing

The Standardized Field Sobriety Test (SFST) are three tests administered and evaluated by local law enforcement officers to obtain validated indicators of impairment and establish probable cause for arresting individuals for DUI / DWI. These standardized sobriety tests were developed as a result of research sponsored by the National Highway Traffic Safety Administration (NHTSA) and conducted by the Southern California Research Institute. A training program was developed and is available through NHTSA to help local police officers become skilled at detecting DUI / DWI suspects.  The standardized sobriety test training helps police officers describe the behavior of DUI / DWI suspects and present effective testimony in court.

There are three standardized field sobriety tests:

• The Horizontal Gaze Nystagmus (HGN) Test
• The Walk and Turn Test
• The Standing One Leg Test

Combined Measures

When the standardized sobriety tests are combined, police officers are accurate in 91 percent of cases, overall, and in 94 percent of cases if explanations for some of the false positives are accepted (Stuster and Burns, 1998).

The original NHTSA research found different accuracies for the SFST Battery than reported in the more recent study. Tharp, Burns, and Moskowitz (1981) reported accuracies of 77 percent for the HGN, 68 percent for the Walk and Turn, and 65 percent for the One Leg Stand components; 81 percent of officers’ arrest decisions at 0.10 BAC were correct when all three measures were combined. In contrast, Stuster and Burns (1998) found greater accuracies in making arrest decisions on the basis of SFST results in their study at 0.08 percent BAC, as described previously and summarized in the following table.

Comparison of Standardized Field Sobriety Tests Accuracies 1981 vs. 1998

Study:  Combined Tharp, Burns, & Moskowitz (1981)

• BAC:  0.10
• HGN:  77%
• WAT: 8%
• OLS: 65%
• Combined: 81%

Study: Stuster & Burns (1998) 

• BAC: 0.08
• HGN:   88%
• WAT:  79%
• OLS:  83%
• Combined:  91%

The greater component and overall accuracies found during the 1998 study are attributable to 17 years of law enforcement experience with the SFSTs since the original study and a lower criterion BAC than in the original study (i.e., 0.08 vs. 0.10 percent).
[/av_textblock]