Are Field Sobriety Tests Accurate in Determining DUI?

Many DUI lawyers say that submitting to a field sobriety test during a traffic stop is not advisable.  For years, DUI defense attorneys have been claiming that the National Highway Traffic Safety Administration's (NHTSA) Standardized Field Sobriety Tests are inaccurate, poorly constructed tests that are designed for the subject's failure. 

Furthermore, argue many DUI defense lawyers, the police officers conducting the tests have often been inadequately trained to properly administer the tests and accurately assess the results. Proponents of the field sobriety tests argue that the tests are a valid and useful tool for identifying driver impairment, dismissing the objections of DUI lawyers as an unsubstantiated defense strategy.  

However, notable researchers and statisticians have demonstrated that field sobriety tests are flawed and improperly administrated with subjective results. Dr. Spurgeon Cole is one such researcher.  Dr. Cole is a retired psychology professor at Clemson University.  His area of expertise is the study of measurements, and he asserts that Standardized Field Sobriety Tests (SFSTs) are "failure-designed."  

In one study by Dr. Cole, fourteen police officers were shown video of twenty one subjects performing SFSTs and asked to determine their impairment based on the results of the tests.  The officers determined that nearly half (46%) of the participants were impaired by alcohol. In fact, all twenty one participants had a BAC of 0.00%--completely sober.

According to Dr. Cole, these results are not much better than a random guess.  "If you use all of [the field sobriety tests], and do them right you are only 26 percent better than chance, 74 percent as much error as you would have if you just randomly guessed."  His results are supported by the research of other experts.

Research conducted by Board-Certified Forensic Psychologist Stephen Rubenzer, Ph.D., using the Horizontal Gaze Nystagmus (HGN) to determine driver impairment is greatly flawed.  According to his research, officers using only HGN as a measure of impairment falsely identify 64% of drivers as having a BAC between o.05 and 0.09%.  If an officer has only been briefly trained in the use of SFSTs, his rate of error is as high as 75%, even when the HGN test is used in conjunction with other field tests.

The other commonly used tests are the Walk and Turn and the One Legged Stand.  These tests may be difficult to perform, especially for drivers with limited physical capabilities.  In Dr. Rubenzer's study, it was determined that officers often judge a participant's performance based on personal bias--including how the driver smells or his speech clarity--and not, in fact, based on performance alone.  

He further reports, "A recent survey of British police surgeons found about half expressed concerned about the SFSTs being too difficult or the grading too harsh. Amongst those with advanced credentials (a Diploma of Medical Jurisprudence or Diploma of Forensic Medicine) over 60% of respondents expressed reservations for the Walk and Turn and One Legged Stand."  

Even police experts have reservations about the validity of these tests. The research explained here is in no way intended as legal advice, nor should it take the place of counsel from a DUI lawyer. It does illustrate that there are strong objections to the validity of the NHSTA's Standardized Field Sobriety Tests, and that there are questions about the effectiveness of officer training.  

Whether or not you submit to field sobriety testing during a traffic stop is your own decision; however, it is important to be well-informed of your rights.  You are not required by Oklahoma law to submit to any field sobriety test or roadside portable breath test.  Under Oklahoma's Implied Consent doctrine, however, you are required to submit to chemical blood analysis following a DUI arrest. If you have been arrested for DUI, contact an experienced DUI lawyer in Oklahoma City.  Your attorney can evaluate all circumstances of your arrest and may be able to effectively challenge any evidence obtained from field sobriety tests.

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