Three Reasons That DUI Field Sobriety Exercises Are Unreliable

The police cruiser pulls in behind your vehicle, and theresults NHTSA had hoped for to conclude that the
officer flips on his lights. You pull over. You roll downfield sobriety tests were scientifically valid. Of the 118
your window as the officer approached your driverindividual arrested, 32% were had a blood alcohol
side door. He asks you if you had anything to drinkcontent level of under .10.
tonight. Then, he asks you to step out of the car. On2. The exercises cannot differentiate between
the side of the road, he asks you if you would beimpairment caused by alcohol and impairment caused
willing to take his "Field Sobriety Tests". The officerby lack of sleep or coordination.
begins by reading you instructions for the "tests" andEven if it can be assumed that the officers are able to
then demonstrates what he wants you to perform.judge impairment by the field sobriety tests, it is
The two psychomotor "tests" a Florida DUI cop willimpossible to conclude that the impairment is a result
request you to perform are the walk and turn and theof alcohol as opposed to just being tired or being
one-legged stand. After you perform, the officer willclumsy. For example, in 1994, Spurgeon Cole, a clinical
likely conclude that you failed his "tests", and place youpsychologist and researcher with Clemson University,
under arrest for DUI.performed a study on the Field Sobriety Exercises
The exercises the cop used to arrest you aretesting the hypothesis that completely sober people
unreliable. There are three main reasons these testswould find the exercises difficult to perform and, as a
are unreliable and should not be given any validity inresult, would be judged "impaired by alcohol" by
court: The scientific studies on the test do not showofficer's viewing their performance.
them to be valid; the exercises cannot differentiateIn the Study, Fourteen police officers rated the
between impairment caused by alcohol and impairmentperformance of 21 individuals what had completed the
caused by lack of sleep or coordination, and thefield sobriety tests. The officers had a mean
exercises are abnormal tests that should not be usedexperience level of 11.7 years, and all had completed
to test normal faculties.the state DUI training program and had field experience
1. The Science does not back up the validity of thewith DUI detection.
field sobriety tests.The participants consisted of 10 males and 11 females,
So in the 1970s, NHTSA funded a research project tobetween 21 and 55 years of age, with no known
study field sobriety tests. The studies evaluateddisabilities. The participants completed six different field
whether or not field sobriety tests could predictexercises, including the walk and turn, finger to nose,
whether subject was above or below a.10% BAC, theand one legged stand. The officers watched the
presumptive level of intoxication in California, Florida,performance on video. At the end of the video, all 21
and many other States at the time of the studies.officers were asked to determine, yes or no, if the
Results of 1977participants were impaired and should not be driving.
Interestingly, NHTSA's funded research first concluded3. The field sobriety tests are abnormal exercises that
that the alphabet test and finger to nose test were notshould not be utilized to attempt to gauge normal
recommended for use as sobriety tests because theyfaculties.
did not add anything to the predictability of theIn Florida, a DUI Attorney will tell you it is only against
subject's influence by alcohol. It is therefore surprisingthe law to drink and drive to the extent that one's
that police officers continue to use both of thesenormal faculties are impaired by the drinking. Only then
exercises today in DUI investigations, considering thatwould the driver be guilty of DUI. But clearly, the very
the "bible" of Police Officer DUI training comes fromtests such as the walk and turn on a line, or standing
the Student Manual published by NHTSA.on one foot, are abnormal exercises. What the officer
Even more interestingly, the officer's participating in theshould be testing is whether the accused is able to
1977 study had an error rate of 47%! Of the 101walk normally, or stand normally. As a result, the tests
people that the DUI officer's concluded were impaired,are truly designed for the individual to fail.
47% of them had a blood alcohol content of less thanBecause of the foregoing three reasons, the field
.10 (the legal limit at the time).sobriety exercises are inherently unreliable. A DUI
So in 1981, NHTSA felt the need to try again. However,Attorney should bring these to the attention of the Jury
the results of this test were not the overwhelmingwhen trying your DUI case.