Field Sobriety Tests

   The field sobriety tasks or FST's are often given by the police in conjunction with any DUI arrest in the State of Tennessee.  It is important to note that these tests are designed to fail.  The police only record errors made by the accused.  Most people absolutely sober would find these tests difficult to perform.  Police are trained to notice even the slightest variance by the defendant.

 Types of Field Sobriety Tests

Horizontal Gaze Nystagmus

   Nystagmus is the involuntary jerking of the eye. It can be an
indication of intoxication. However, the occurrence of
nystagmus is not dependent upon the presence of an intoxicant
in the body. Substances that would not interfere with driving
ability can produce nystagmus, and nystagmus may be congenital
or caused by structural neurologic disease.

   Examples of possible manifestations of alcohol impairment
emerging during nystagmus test include the inability to keep
the head still; noticeable swaying, and the utterance of
incriminating statements. Points are not deducted, however,
for any of these behaviors.

   Examples of conditions that may interfere with suspect’s
performance of the nystagmus test include a suspect having an
artificial eye; having damaged or very weak vision in one eye;
eye irritants such as wind, dust, and rain; and visual and
other distractions which impede the test, such as traffic,
blinking lights, rain, etc. Some persons who are not under the
influence may exhibit nystagmus.

   Nystagmus may also be caused by certain pathological disorders
such as brain tumors, brain damage and some diseases of the
inner ear.

Walk and Turn

   In this test, the subject assumes a heel-to-toe stance with
the subject’s arms down at her side. The subject is to
maintain this position until the officer tells her to begin
walking. At that time, pursuant to the instructions given
bythe officer during the instruction phase, the subject is to
take 9 heel-to-toe steps down a real or imaginary, turn around
and take 9 heel-to-toe steps back up the line. The turn is not
a pivot, but instead is made by taking a series of small steps
with one foot, keeping the front foot on the line. While
walking, the subject is to keep her arms at her side, watch
her feet at all times, and count her steps out loud. Examples
of conditions that may interfere with suspect¹s performance of
the walk and turn test include wind and weather conditions;
the suspect being over the age of sixty; the suspect being
fifty pounds or more overweight; the footwear of the suspect;
and highway traffic.

One Leg Stand

   The instructions for this test are given to the subject while
the subject stands with his feet together, and arms down at
his side until told to start. The instructions which are
supposed to be given to the subject (with accompanying
demonstration) are for the subject to stand on one leg (either
leg), holding out the other foot approximately 6 inches off
the ground, foot pointed forward so the raised foot is
approximately parallel to the ground. While standing, the
subject may be instructed to maintain this position while the
officer estimates thirty second or the subject may be told to
count out loud (one thousand and one, one thousand and two,
and so on). Either way, the subject is to keep his arms at his
sides at all times and watch the raised foot. Examples of
conditions which may impede a suspect’s ability to perform
this test include a test surface which is not dry and level;
the suspect being over the age of sixty; the suspect being at
least fifty pounds overweight; footwear which impedes the
performance of the test, such as heels; and certain medical
problems and disabilities.

Non Standardized Field Sobriety Tests

   There are other, non-standardized field sobriety tests which
have been approved for use by various organizations.  These tests include, but are not limited to, the finger to nose test, the finger count test, the hand pat test,
the alphabet test, the reverse counting test, and the coin
pickup test.