DUI FST Accuracy

Gilbert DUI Lawyer for Standard Field Sobriety Test (SFST) Accuracy Defense

Standard Field Sobriety Test (SFST) Accuracy | Accuracy Statistics for SFST (S) | Gilbert DUI Lawyer

Accuracy of DUI Standard Field Sobriety Tests (SFST) Overview

For many reasons even Standard Field Sobriety tests have been known to be unreliable or inaccurate. Some studies indicate that persons who are not under the influence of drugs or alcohol; and not driving impaired; are unable to pass the SFST. As a result, they should be admitted only as preliminary evidence against a suspect, and not solely to convict someone of DUI. In order for the SFST to be accurate, must be administered precisely in accordance with the NHTSA guidelines. However, SFSTs are rarely in always in precise compliance with the NHTSA rules and guidelines. These guidelines require the presence of appropriate testing conditions; equipment; and even appropriate candidate requirements. These rules and guidelines relate to: Standardized and approved NHTSA tests have requirements that relate to location; environment; nearby traffic; equipment, angle, and lighting for the HGN Eye Test; climate and weather conditions; candidacy of suspect for SFST considering age, weight, or medical conditions; individual balance and coordination skills; instruction and administration; language barriers; judging; and reporting.

Statistics of Accuracy Rates for Standard Field Sobriety Tests (SFST)

The most recent studies reported by NHTSA were from 1998, in the following statistics. At first glance, these percentages are relatively high. However, these statistics reflect different experience (or more experience) in police officers who had conducted the tests in operational conditions. The NHTSA studies also suggested that the accuracy percentages had increased from 1981 statistics due to the fact that the officers had more operational experience in conducting the tests in the second trial studies reported in 1998.

SFST(s) 1998 SFST Battery Reported by NHTSA sponsored Studies

Horizontal Gaze Nystagmus (HGN)88%
One-Leg Stand (OLS)83%
Walk-and-Turn (WAT)79%
3 SFST (s) combination91%

Note: Variances may exist by state statute; state case law, court decisions; or independent research studies conducted and are not included in the NHTSA statistics reported above.

Challenges made by criminal defense attorneys with regard to the accuracy of the statistics reported by NHTSA in 1998 historically have been that:

  • Not all officers possess the same experience level (some have years more experienced than others at conducting the tests);
  • Not all conditions are optimal; (weather, lighting, terrain, location, equipment)
  • Not all suspects are good candidates for SFST: (based on guidelines for weight, age, pre-existing medical conditions; or physical fitness levels)
  • Statistics are not current: These studies were reported in 1998

Gilbert DUI lawyer for Defense of Standard Field Sobriety Test Results

Whether or not your DUI arrest involved your participation in SFST (s) or not; you should always consult an experienced DUI defense attorney before “pleading guilty”. There may be defenses that can be used to get evidence suppressed; your case dismissed; or charges and sentencing reduced based on the facts of your case. The Law Office of James Novak, defends DUI charges and evidence exclusively in Phoenix-Metro and East Valley Cities of Tempe, Mesa, Chandler, Gilbert, Scottsdale, and Phoenix. James Novak, Attorney at law is an experienced trial lawyer and former prosecutor in Maricopa County. For active charges in these cities, he offers a free consultation. Call for legal help today ( 480) 413-1499!

Law Office of James Novak, PLLC
4500 S. Lakeshore Drive
Tempe AZ 85282
(480) 413-1499


Arizona DUI & Criminal Defense
Serving Tempe, Phoenix,Mesa, Phoenix , Gilbert, Mesa, Scottsdale, AZ
Free Consultation! Call (480) 413-1499