Field Sobriety
Tests
For persons accused of DUI in California, Field
Sobriety Tests are generally used to determine
if a person has been driving while intoxicated,
and whether or not there is probable cause to
arrest the driver for DUI.
Most drivers are not aware that there
are only three recognized field
sobriety tests. The Standardized Field Sobriety
Test (SFST) is a battery of three tests
administered and evaluated in a standardized
manner to obtain validated indicators of
impairment and establish probable cause for
arrest. These 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 formal program of training was
developed and is available through NHTSA to help
police officers become more skillful at
detecting DUI suspects, describing the behavior
of these suspects, and presenting effective
testimony in court. Formal administration and
accreditation of the program is provided through
IACP. Unfortunately, many officers either did
not attend the formal training, or relax the
strict standards of the three tests, sometimes
adding tests that are not recognized. The three
tests of the SFST are:
- the horizontal gaze nystagmus (HGN)
- the walk-and-turn
- the one-leg stand.
These tests are administered systematically
and are evaluated according to measured
responses of the suspect.
HGN Testing
Horizontal gaze nystagmus is an involuntary
jerking of the eyeball which occurs naturally as
the eyes gaze to the side. Under normal
circumstances, nystagmus occurs when the eyes
are rotated at high peripheral angles. However,
when a person is impaired by alcohol, nystagmus
is exaggerated and may occur at lesser angles.
An alcohol-impaired person will also often have
difficulty smoothly tracking a moving object. In
the HGN test, the officer observes the eyes of a
suspect as the suspect follows a slowly moving
object such as a pen or small flashlight,
horizontally with his eyes. The examiner looks
for three indicators of impairment in each eye:
if the eye cannot follow a moving object
smoothly, if jerking is distinct when the eye is
at maximum deviation, and if the angle of onset
of jerking is within 45 degrees of center. If,
between the two eyes, four or more clues appear,
the suspect likely has a BAC of 0.10 or greater.
NHTSA research indicates that this test allows
proper classification of approximately 77
percent of suspects. HGN may also indicate
consumption of seizure medications,
phencyclidine, a variety of inhalants,
barbiturates, and other depressants.
Divided Attention Testing:
The walk-and-turn test and one-leg stand test
are “divided attention” tests that are supposed
to be easily performed by most sober people.
They require a suspect to listen to and follow
instructions while performing simple physical
movements. Impaired persons have difficulty with
tasks requiring their attention to be divided
between simple mental and physical exercises.
In the walk-and-turn test, the subject is
directed to take nine steps, heel-to-toe, along
a straight line. After taking the steps, the
suspect must turn on one foot and return in the
same manner in the opposite direction. The
examiner looks for seven indicators of
impairment: if the suspect cannot keep balance
while listening to the instructions, begins
before the instructions are finished, stops
while walking to regain balance, does not touch
heel-to-toe, uses arms to balance, loses balance
while turning, or takes an incorrect number of
steps. NHTSA research indicates that 68 percent
of individuals who exhibit two or more
indicators in the performance of the test will
have a BAC of 0.10 or greater. In the one-leg
stand test, the suspect is instructed to stand
with one foot approximately six inches off the
ground and count aloud by thousands (One
thousand-one, one thousand-two, etc.) until told
to put the foot down. The officer times the
subject for a 30 seconds. The officer looks for
four indicators of impairment, including swaying
while balancing, using arms to balance, hopping
to maintain balance, and putting the foot down.
NHTSA research indicates that 65 percent of
individuals who exhibit two or more such
indicators in the performance of the test will
have a BAC of 0.10 of greater. The effectiveness
of SFST in court testimony and evidence depends
upon the cumulative total of impairment
indicators provided by the three-test battery.
The greater the number of indicators, the more
convincing the testimony. Because SFST is
administered according to national standards and
is supported by significant research, it has
greater credibility than mere subjective
testimony.
Testing Accuracy:
The NHTSA manuals (plural
here, because 6 separate versions
have now been released) say that if the FST
tests are not performed properly, or if
conducted without adhering to the training
protocols, such actions “compromise” the
validity of these evaluations.
The HGN evaluation, when performed correctly
on proper subjects, had a 77% “claimed”
reliability rating. The Walk-and-Turn exercise,
when conducted properly on a qualified subject
on a dry, level surface, was found to be 68%
reliable. The One-Leg-Stand exercise, when
conducted properly, on a qualified subject on a
level, dry surface and under proper instructions
and where correctly demonstrated and scored,
reportedly yields about 65%
reliability. Cumulatively, if all are done
correctly, up to 83% correlation to a BAC of
0.10% or more may be expected.
Knowledgeable criminal defense lawyers know
that 98% or more of the officers administering
these evaluations do them wrong, or conduct them
in a manner (or on a test subject) not approved
by the SFST manual, or grade the evaluations
improperly, as per the manual, or ALL OF THE
ABOVE. When done incorrectly, these
evaluations have ZERO predicted reliability.
Also, recent research and scientific review of
the testing protocols and scoring methodology
have brought the NHTSA “Standardized Field
Sobriety Tests (“SFSTs”) into serious question.
More and more courts are now saying “no” to
these questions. In a recent New Mexico case, a
high-level court has declared that the person
who “developed” the tests (Dr. Marcelline Burns)
was not qualified to testify as an expert
witness about the scientific principles behind
the HGN test. (Lasworth v. State, 42 P.2d
844 (N.M. App. 2001).
Alternative Testing Methods:
Sometimes, an officer will encounter a
disabled driver who cannot perform the SFST. In
such cases, some other battery of tests such as
counting aloud, reciting the alphabet, or finger
dexterity tests may be administered. Several
appellate court decisions have indicated that,
if you administer a test that requires the
subject to respond orally in other than a
routine information-giving fashion, such as
requiring them to indicate the date of their
sixth birthday, and if they are in custody at
the time, you should administer the Miranda
warning first, because you are seeking
information from them that is testimonial or
communicative in nature.
Tests given by some officers may include
reciting the alphabet (or a portion thereof),
picking up coins off the ground, patting or hand
clapping, estimating time, counting backwards,
reciting the alphabet, touching fingers to the
thumb in a pattern set by the officer, or
touching index fingers to the tip of the nose
while the person’s eyes were closed and head
tilted back. Some have in the past involved
strange, one-legged tapping on the roadway with
a raised foot. These “made-up” tests were
administered to subjects without any scientific
or empirical basis for reliability in detecting
an impaired driver. These tests were designed
for failure, not for fairness. Even worse,
police officers often forced people to
perform these voluntary evaluations, thereby
violating these citizens’ rights.
Some “non-standardized” tests are so ridiculous
and difficult that proof of non-validity was
easy with almost any jury or judge. Today,
officers who lack NHTSA training invariably
cannot cite any studies or scientific research
which “validated” their tests, the scoring
(e.g., “pass” or “fail”) or their testing
methods. Almost always, no scoring system is
used on tests which do not adhere to NHTSA
guidelines. If non-standardized tests are used,
the number of errors that are required for a
subject to fail is totally subjective with each
officer. Hence, the untrained officer is usually
an easy target for a skilled and knowledgeable
criminal defense attorney who knows the
“limitations” of these field tests.
The
Voluntary Nature of FST Tests:
Recognize that these tests are completely
voluntary. These voluntary “tests” (yes,
voluntary) are developed NHTSA and implemented
by police agencies to assist law enforcement
officers in making roadside determinations as to
whether a motorist is under the influence of
alcohol or drugs. Through the performance of
these tests or evaluations, the officer
subjectively determines how the motorist reacts
to and performs the requested tasks.
Almost EVERY knowledgeable DUI / DWI attorney
will say to you, “NO. Don’t attempt ANY
‘field tests’ — EVER.” That is because many
studies have concluded that the SFSTs are
“designed to fail” even sober drivers.
A motorist's alleged poor performance on
field evaluations may provide the “probable
cause” (legal justification) an officer needs to
arrest a person for impaired driving and may
also become part of the proof used to later
convict the person at trial. Therefore, it is
very important that, in defending you, your
defense attorney know as much or more about
these tests as the police, if he or she is going
to defend you.
DUI defense counsel usually challenges the
subjective nature of the evaluations, the
accuracy of the principles behind the tests, the
accuracy of the administration of the tests, the
credibility of the officer who “requested” the
tests, and challenge all circumstances connected
with the evaluations. An attorney representing
you must attack the factual and legal issues
that may arise regarding the officer's scoring
and evaluation of the field tests.
The reason that most credible scientists
across America (and in other countries) are
unwilling to categorize field tests — even
NHTSA's tests — as being “scientific” is that
too many variables are involved in roadside
testing to ever eliminate pure chance and
non-controlled circumstances from the equation
(e.g., environmental conditions such as lighting
and roadway slope).
Even NHTSA admits that under optimal conditions
(i.e., in an air-conditioned, well lighted room)
35% of sober, drug-free subjects get inaccurate
results on the one leg stand test, 32% of sober
subjects get flawed results on the walk and
turn, and 23% of sober subjects are inaccurately
said to be “over the legal limit” on the
horizontal gaze nystagmus test. By comparison,
polygraph (lie detector) tests are more than 90%
accurate when conducted by a qualified
operator), and (absent a stipulation by both
parties) are still not permitted into evidence
by most courts.
Roadside Alcohol Screening Tests:
A portable breath testing device may be used
by police officers in determining whether or not
a motorist is under the influence of alcohol.
California had previously banned the use of
these voluntary “non-evidential” screening
devices for use at trial, but allows it at a
pre-trial hearing at which “probable cause” for
arrest is involved.
Like other “field tests”, these devices are
used at the roadway. Often, police officers do
not regularly check the devices for
calibration. Furthermore, the manufacturer’s
instructions (e.g., failing to observe a 15
minute deprivation period, waiting at least 4
minutes between tests, or clearing the prior
test results) for proper use are routinely
ignored. California’s Administrative Code, Title
17, contains all the information necessary for
what constitutes a valid blood or breath test.
Some police agencies try to use these
roadside testers as evidential
tests. This is accomplished when a small printer
is attached to the breath test apparatus. Unless
your jurisdiction uses such a device as an
official state-mandated breath test, no person
should ever submit to these devices and risk a
false positive result and almost certain
arrest. Politely decline to give this voluntary
sample, although be aware that refusal of an
official breath or blood test later can be
considered a refusal, triggering a license
revocation.
If you have any other questions, make sure you
speak with, visit, or
email
a
qualified attorney.
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