DWI Detection and Standardized Field Sobriety Testing: An

DWI Detection and Standardized Field
Sobriety Testing:
An Objective Look at the NHTSA DWI Training Manual
by
Attorney Ryan Michael Paulus of the
Paulus Law Firm LLC
www.pauluslawfirm.com
www.missouridwihelp.com
Copyright October 2008
Each year alcohol related traffic accidents claim
thousands of lives. In 2002, 41 percent of all traffic
fatalities were alcohol-related.1 Driving while impaired
isn’t activity that’s limited to only to alcoholics and
drug users. In fact, a 1991 Gallup Survey of 9,028 drivers
nationwide found that 14% of the respondents reported they
drove while close to or under the influence of alcohol
within the last three months.2 Driving while intoxicated
(DWI) is a common crime that is committed by people from
all facets of our society.
In response to the growing societal concerns about DWI
the National Highway Traffic Safety Administration
contracted a series of studies that eventually lead to
creation of the NHTSA “DWI Detection and Standardized Field
Sobriety Testing” manual. The purpose of the manual was to
1
DWI Detection and Standardized Field Sobriety Testing, NHTSA Student Manual, pg II-1 (February,
2006 Edition).
2
Id.
1
provide law enforcement entities with a standardized
training manual for the prosecution of DWI defendants. This
NHTSA manual is taught to law enforcement officers in every
state in the country. The manual lays out the tests and
procedures that a reasonably prudent and careful officer
should follow prior to making the arrest decision of a DWI
suspect. This manual, the validity of the methods taught in
it, and the science behind these methods have been an area
of contention for some time. In the following pages we will
look at the manual and the alcohol detection methods taught
in it. We will then examine the science behind these
detection methods and the criticisms of that science.
WHAT NHTSA SAYS ABOUT DWI DETECTION
According to the 2006 NHTSA student manual, DWI
detection is defined as the entire process of identifying
and gathering evidence to determine whether or not a
suspect should be arrested for a DWI violation.3 The manual
goes on to say that the detection process ends when the
officer decides either to arrest or not to arrest the
individual for DWI.4 Furthermore; that “decision, ideally,
is based on all of the evidence that has come to light
3
4
Id. at IV-1
Id.
2
since your attention first was drawn to the suspect.”5
“Effective DWI enforcers do not leap to the arrest/no
arrest decision.”6
The manual teaches that there are three separate
phases to DWI detection.7 Phase one is observing the driver
operate the vehicle; phase two is personal contact; and
phase three is the pre-arrest screening.8
PHASE ONE (Observing the driver operate the vehicle)
In phase one, the officer observes the vehicle in
operation and based off this observation decides whether
there is sufficient cause to stop the vehicle.9 The officer
needs a reasonable and articulatable suspicion that a crime
has or is being committed in order to stop the vehicle.
This standard is usually satisfied by the vehicle operator
committing some minor traffic violation.
The manual describes certain visual cues that drivers
who are impaired frequently exhibit. Those cues are: slowed
reactions, impaired judgment as evidenced by a willingness
to take risks; impaired vision, and poor coordination.10 The
manual goes on further to list specific cues that police
5
Id.
Id.
7
Id. at IV-2
8
Id.
9
Id. IV-4
10
Id. at V-2
6
3
officers may use to detect impaired drivers during phase
one.11
Those cues are:
weaving, weaving across lane lines, straddling a lane line,
swerving,
turning
with
a
wide
radius,
drifting,
almost
striking object or vehicle, stopping problems, accelerating
or decelerating rapidly, varying speed, slow speed, driving
in opposing lanes or wrong way on one way street, slow
response to traffic signals, slow or failure to respond to
officer’s signals, stopping in lane for no apparent reason,
driving without headlights at night, failure to signal or
signal
inconsistent
with
action,
following
to
closely,
improper of unsafe land change, illegal or improper turn,
driving
on
other
inappropriately
unusual
behavior,
steering
wheel,
erratically
driver’s
motor
in
or
head
vehicle
than
designated
response
eye
to
officer,
fixation,
slouching
roadway,
in
face
close
protruding
form
vehicle,
difficulty
gripping
seat,
obscenely,
controls,
inappropriate
tightly
the
to
stopping
the
the
gesturing
windshield,
difficulty
exiting
or
the
with
vehicle,
fumbling with driver’s license or registration, repeating
questions
or
comments,
swaying,
unsteady,
or
balance
problems, leaning on the vehicle or other object, slurred
speech,
slow
to
respond
to
officer,
provides
incorrect
information, odor of alcoholic beverage from the driver.12
11
12
Id. at V-3
Id. at V-4 – V-7
4
The manual also includes pictures that show the visual
cues. Some of the included pictures:
Turning with a wide radius:
Weaving:
Swerving:
5
Drifting:
The majority of the items on this list are factors
that tend to show that a driver does not have the ability
to divide attention among various tasks.
For example the
flashing emergency lights divert the driver’s attention and
require that driver to divide attention between driving and
responding to the stop command.13 The manual states that
“[u]nder the influence of alcohol and/or other drugs, a
diver’s ability to divide attention is impaired.”14 We will
13
14
Id. at V-10
Id. At V-9
6
explore later why this conclusion is poorly supported by
research.
PHASE TWO (Personal Contact)
In phase two the officer must observe and interview
the driver face-to-face and observe the driver’s exit and
walk from the vehicle.15
During phase two the manual list’s a number of cues
that an officer should look for to support his DWI arrest
decision. Those cues are:
Bloodshot eyes; soiled clothing; fumbling fingers; alcohol
containers; drugs or drug paraphernalia; bruises, bumps or
scratches;
unusual
actions;
slurred
speech;
admission
of
drinking; inconsistent responses; abusive language; unusual
statements; smell of alcoholic beverages; marijuana; cover
up odors like breath sprays; unusual odors;16 shows angry or
unusual reactions; cannot follow instructions; cannot open
the
door;
leaves
the
vehicle
in
gear;
climbs
out
of
vehicle; leans against vehicle; keeps hands on vehicle for
balance.17
The manual also provides some questioning techniques
that an officer can use to trip up a suspected DWI
offender. This technique teaches officers to ask questions
in a way that’s confusing or compound. The examples the
15
Id.
Id. at, VI-3.
17
Id. at VI-6
16
7
manual gives are to ask for two things simultaneously
“requesting the driver produce both a driver’s license and
registration”;18 ask interrupting or distracting questions
“Without looking at your watch, what time is it right
now?”19; and ask unusual questions like “what is your middle
name?.”20 The manual gives no reference to any research that
shows that these techniques have any validity.
The manual goes on to explain how an officer should
perform the alphabet, count down and finger count
technques. It must be noted that the manual does state that
“These techniques are not as reliable as the standardized
field sobriety tests…” and “THESE TECHNIQUES DO NOT REPLACE
THE SFST.”21
First the manual describes the Alphabet technique. The
Alphabet technique requires the subject to recite a part of
the alphabet.22 The officer is instructed to ask the suspect
to recite the alphabet beginning with a letter other than A
and stopping at a letter other than Z. This test is
hypothetically designed to divide the driver’s attention
because the driver must concentrate to begin at an unusual
18
Id at VI-4
Id. at VI-5
20
Id..
21
Id at VI-4.
22
Id. at VI-5
19
8
starting point and recall where to stop.23 There is no peer
reviewed scientific data that validates this test for use
in DWI detection and I have found no data that lends any
validity to this test for use in DWI detection.
The next technique that the manual lists is the “Count
Down.” This technique requires the subject to count out
loud 15 or more numbers in reverse sequence.24 The example
the manual gives is to ask the driver to count out loud
backwards, starting with the number 68 and ending with the
number 53.25 Again, the rational that the manual gives for
this test is that it divides the attention of the driver
because the driver must continuously concentrate to count
backwards while trying to recall where to stop.26 However;
the manual does not site to any scientific research or peer
reviewed studies to back up this assertion.
The next technique that the manual teaches is the
“Finger Count.” This technique requires that suspect to
touch the tip of the thumb in turn to the tip of each
finger on the same hand while simultaneously counting up
one, two, three, four; and then to reverse direction on the
fingers while simultaneously counting down four, three,
23
Id.
Id.
25
Id.
26
Id.
24
9
two, one.27 Again, the manual fails to cite any research
that supports this as a viable DWI detection technique.
PHASE THREE (Pre-Arrest Screening)
During phase three the officer is taught to
“administer structured, formal psychophysical tests.”28 The
manual goes on to say that based on these tests the officer
must decide whether there is sufficient probable cause to
arrest the driver for DWI and if so then the officer should
arrange for or administer a preliminary breath test.29
The manual states that psychophysical tests are
methods of assessing a suspect’s mental and physical
impairment and focus on the abilities needed for safe
driving: balance, coordination, information processing.30
The Three psychophysical tests that are standardized are
the Horizontal Gaze Nystagmus test, the Walk-and-Turn, and
the One-Leg Stand.
Horizontal Gaze Nystagmus
Horizontal Gaze Nystagmus (HGN) refers to an
involuntary jerking occurring as the eyes gaze toward the
27
Id. at VI-6.
Id.
29
Id.
30
Id. at VII-1.
28
10
side.31 The manual states that the Horizontal Gaze Nystagmus
test is the most reliable field sobriety test.32 In
administering the HGN test, the officer has the suspect
follow the motion of a small stimulus with the eyes only.
The officer is instructed to always begin with the suspects
left eye and examine each eye for three specific clues.33
The clues are:
1. as the eye moves from side to side, does it move
smoothly or does it jerk noticeably? (As people become
impaired by alcohol, their eyes exhibit a lack of smooth
pursuit as they move from side to side.)34
2. when the eye moves as far to the side as possible
and is kept at that position for several seconds, does it
jerk distinctly? (Distinct and sustained nystagmus at
maximum deviation is another clue of impairment.)35
3. as the eye moves toward the side, does it start to
jerk prior to a 45-degree angle? (Onset of nystagmus prior
to 45-degrees is another clue of impairment.)36
The maximum number of clues that may appear in one eye
is three and the total number for any suspect is six.37 It
31
Id. at VII-2.
Id.
33
Id.
34
Id. at VII-3.
35
Id.
36
Id.
37
Id.
32
11
is unclear to the author of this article how signs of
impairment could be present in one eye but not the other?
The manual states that the “original research shows that if
four or more clues are evident, it is likely that the
suspect’s blood alcohol concentration is above 0.10.”
38
The NHTSA instructs that the horizontal Gaze nystatmus
test be administered in the following manner. The suspect
is given the following instructions from a safe position.
“I am going to check your eyes.”39 “Keep your head still and
follow this stimulus with your eyes only.”40 “Keep following
the stimulus with your eyes until I tell you to stop.”41 The
officer is then instructed to place the stimulus
approximately 12-15 inches from the suspect’s nose and
slightly above eye level.42 The officer may observe Resting
Nystagmus at this time.43 The officer then needs to check
the suspects’ eyes for equal tracking by moving the
stimulus smoothly across the suspect’s entire field of
vision to see if the eyes track the stimulus together or if
one lags behind the other.44 Next the officer is instructed
to check to see if both the pupils are of equal size, if
38
Id.
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VIII-6 ( 2002
Edition).
40
Id.
41
Id.
42
Id.
43
Id.
44
Id.
39
12
they are not it may indicate a head injury.45 The officer
must then check the suspect’s left eye first by moving the
stimulus to his right smoothly at a speed that requires
approximately two seconds to bring the suspect’s eye as far
to the side as it can go and then back to the left across
the suspect’s face checking if both eyes pursue smoothly.46
Each movement of the stimulus should take approximately two
seconds out and two seconds back for each eye.47 The officer
must then repeat the procedure.48
After the officer has checked both eyes for lack of
smooth pursuit, he must then check the eyes for distinct
nystagmus at maximum deviation, again beginning with the
left eye.49 Too check this, the officer moves the stimulus
until the suspect’s eye has gone as far to the side as
possible and then holds the eye in that position for a
minimum of four seconds.50 At this time, the officer checks
that eye for distinct and sustained nystagmus.51 The officer
then moves the stimulus across the suspects face in order
45
Id.
Id. at pg VIII-7.
47
Id.
48
Id.
49
Id.
50
Id.
51
Id.
46
13
to check the right eye for a minimum of four seconds and
then repeats the procedure for both eyes.52
Lastly the officer checks for onset of nystagmus prior
to 45 degrees.53 The officer starts by moving the stimulus
towards the right at a speed that would take approximately
four seconds for the stimulus to reach the edge of the
suspect’s shoulder while carefully watching the eye for any
sign of jerking.54 If the officer sees any sign of jerking,
he is to stop and verify that the jerking continues.55 The
officer then moves the stimulus to the left at a speed that
would take approximately four seconds for the stimulus to
reach the edge of the suspect’s shoulder while watching for
any signs of jerking.56 The Officer then repeats the
procedure for both eyes.57 If the suspect’s eyes start
jerking before they reach 45 degrees, the officer needs to
check to see that some white of the eye is still showing on
the side closest to the ear; if no white of the eye is
showing, either the officer has taken the eye too far to
the side or the person has unusual eyes that will not
deviate very far to the side.58 The manual states that this
52
Id.
Id.
54
Id.
55
Id.
56
Id.
57
Id.
58
Id.
53
14
test was validated according to these instructions and
deviating from these instructions would compromise the
standardization and therefore the scientific validity of
the test.59
Walk-and-Turn
The manual divides the walk-and-turn test into two
stages; the instruction stage, and the walking stage.60
The instructions stage requires the suspect to stand
with his feet in heel-to-toe position, keep his arms at his
sides, and listen to the instructions.61 The purpose of the
instruction phase is to divide the subject’s attention
between a balancing task and an information processing
task.62
The walking stage requires the subject to take nine
heel-to-toe steps, turn in a prescribed manner, and take
nine heel-to-toe steps back, while counting the steps out
loud and watching his feet.63 When the subject turns he must
keep his front foot on the line and use the other foot to
take several small steps to complete the turn.64 The walking
59
Id. at VIII-19
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VII-5
(February, 2006 Edition).
61
Id.
62
Id.
63
Id.
64
Id.
60
15
test is designed to divides the subject’s attention among a
balancing task, a small muscle control task, and a shortterm memory task.65
The manual states that the walk-and-turn test “is
administered and interpreted in a standardized manner.”66
The manual gives eight clues that the administrator of the
test must watch for in order to judge the suspect’s
performance.67 Those clues are: 1. can’t balance during
instructions; 2. starts too soon; 3. stops while walking;
4. doesn’t touch heel-to-toe; 5. steps off line; 6. uses
arms to balance; 7. loses balance on turn or turns
incorrectly; and, 8. takes the wrong number of steps.68 The
manual also states that inability to complete the walk-andturn test occurs when the suspect: steps off the line three
or more times; is in danger of falling; or cannot do the
test. The manual goes on to further say that the original
research shows that if a suspect exhibits two or more of
the clues, or cannot complete the test, the suspect’s BAC
is likely to be above 0.10.
69
However; this criterion has
only been shown to be accurate 68 percent of the time.70
65
Id.
Id.
67
Id.
68
Id.
69
Id. at VII-6.
70
Id.
66
16
The manual gives the following instructions for the
walk-and-turn test. The officer instructs the suspect to:
1. “Place your left foot on the line” (real or imaginary).
Demonstrate.71
2. “Place your right foot on the line ahead of the left
foot, with heel of right foot against toe of left foot.”
Demonstrate.72
3. “Place your arms down at your sides.” Demonstrate.73
4. “Keep this position until I tell you to begin. Do not
start to walk until told to do so.”
74
5. “Do you understand the instructions so far?” (Make sure
suspect indicates understanding.)75
For the following instructions the officer is to accompany
his verbal instructions with demonstrations.76
6. “When I tell you to start, take nine heel-to-toe steps,
turn, and take nine heel-to-toe steps back.” (demonstrate 3
heel-to-toe-steps.)77
7. “When you turn, keep the front foot on the line, and
turn by taking a series of small steps with the other foot,
like this.” (Demonstrate).78
71
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VIII-9 ( 2002
Edition).
72
Id.
73
Id.
74
Id.
75
Id.
76
Id.
77
Id.
17
8. “While you are walking, keep your arms at your sides,
watch your feet at all times, and count your steps out
loud.”79
9. “Once you start walking, don’t stop until you have
completed the test.”80
10. “Do you understand the instructions?” (Make sure
suspect understands.)81
11. “Begin, and count your first step from the heel-to-toe
position as ‘One.’”82
Again the manual states that the validation for this
test only applies when the tests are administered in the
prescribed standardized manner and standardized criteria
are employed to interpret that performance.83
Because of the difficulty of understanding how a
suspect is instructed to turn around if included a picture
of the turn taken from the manual.84
78
Id.
Id.
80
Id.
81
Id.
82
Id.
83
Id. at VIII-19
84
Id. at VIII-10
79
18
One-Leg Stand
The one-leg stand is also a divided attention test
that consists of two stages; the instructions stage and the
balance and counting stage.85
During the instruction stage,
the subject must stand with feet together, keep arms at
sides, and listen to instructions.86 This stage divides the
subject’s attention between a balance task and an
information processing task.87
During the balance and counting stage, the subject
must raise one leg, either leg, with the foot approximately
six inches off the ground, keeping raised foot parallel to
the ground.88 While the suspect looks at the elevated foot,
he is to count out loud in the following manner: “one
85
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VII-6
(February, 2006 Edition).
86
Id.
87
Id.
88
Id.
19
thousand and one”, “one thousand and two”, “one thousand
and three” until told to stop.89 The manual say’s that this
stage of the test divides the subject’s attention between
balancing and small muscle control.90
The manual lists four specific clues that and officer
should look for in evaluating a suspect’s performance.
Those clues are: 1. sways while balancing; 2. uses arms to
balance; 3. hops; 4. puts foot down.91 The manual goes on to
say that inability to complete the one-leg stand test
occurs when the suspect puts the foot down three or more
times during the 30-second period; or cannot do the test.92
Lastly the manual states that the original research showed
that when the suspect produces two or more clues or is
unable to complete the test, it is likely that the BAC is
above 0.10.93 “This criterion has been shown to be accurate
65 percent of the time.”94
The instructions for the One-Leg Stand are as follows:
1. “Please stand with your feet together and your arms down
at the sides, like this.” (Demonstrate.)95
89
Id.
Id.
91
Id.
92
Id.
93
Id. at VII-7.
94
Id. at VII-6.
95
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VII-12 (2002
Edition).
90
20
2. “Do not start to perform the test until I tell you to do
so.”96
3. “Do you understand the instructions so far?” (Make sure
suspect indicates understanding.)97
4. “When I tell you to start, raise one leg, either leg,
approximately six inches off the ground, foot pointed out.”
(Demonstrate one leg stance.)98
5. “You must keep both legs straight, arms at your side.”99
6. “While holding that position, count out loud in the
following manner: “one thousand and one, one thousand and
two, one thousand and three, until told to stop.”
(Demonstrate a count, as follows: “one thousand and one,
one thousand and two, one thousand and three, etc.” Officer
should not look at his foot when conducting the
demonstration for officer safety.)100
7. “Keep your arms at your sides at all times and keep
watching the raised foot.”101
8. “Do you understand?” (Make sure suspect indicates
understanding.)102
96
Id.
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VII-12 (2002
Edition).
98
Id.
99
Id.
100
Id.
101
Id.
102
Id.
97
21
9. “Go ahead and perform the test.” (Officer should always
time the 30 seconds. Test should be discontinued after 30
seconds.)103
Observe the suspect from a safe distance, and if the
suspect puts the foot down, give instructions to pick the
foot up again and continue counting from the point at which
the foot touched the ground.104 If the suspect counts very
slowly, terminate the test after 30 seconds.105
The test was standardized according to these
instructions and any deviation from these instructions
would compromise the scientific validity of the test.
The 2006 manual contains this warning in bold and all
caps, following the section on how to administer
Standardized Field Sobriety Tests:106
103
Id.
Id.
105
Id.
106
Id. at VIII-19.
104
22
VALIDATION STUDIES
In this section we will look at the studies that the
National Highway Traffic Safety Administration bases its
manual on.
The manual states that beginning in late 1975;
“extensive scientific research studies were sponsored by
NHTSA through contract with the Southern California
Research Institute (SCRI) to determine which roadside field
sobriety tests were the most accurate.”107 SCRI eventually
published four reports with their findings. Those reports
were Psycophysical Tests for DWI Arrest, 1977; The Visual
Detection of Driving While Intoxicated, Field Test of
Visual Cues and Detection Methods, 1980; Development and
Field Test of Psychophysical Tests for DWI Arrest, 1981;
107
DWI Detection and Standardized Field Sobriety Testing. NHTSA Student Manual, pg VIII-1
(February, 2006 Edition).
23
and Field Evaluation of a Behavioral Test Battery for DWI,
1983.
Psychophysical Tests for DWI Arrest, 1977
The first study contracted by and for the U.S.
Department of Transportations’ National Highway Traffic
Safety Administration on the topic of DWI Detection was
completed in June of 1977. The report was titled
“Psychophysical Tests for DWI Arrest” and was conducted by
Marcelline Burns and Herbert Moskowitz of SCRI.108
The objectives of the study were to evaluate the
currently-used DWI tests, development of more sensitive and
reliable measures, and the standardization of test
administration.109 Six tests were chosen for the evaluation
study and ten officers administered the 6-test battery to
238 participants who were light, moderate and heavy
drinkers.110 The participants were given either placebo or
alcohol treatments that produced BACs in the range of 0 .15%.111 The police officers scored the performance of each
test on a 1 - 10 scale, and on the basis of the entire
battery judged whether the person should be arrested or
108
Burns & Moskowitz; “Psychophysical Tests for DWI Arrest”; Final Report; pg. I; DOT HS- 802 424
(1977).
109
Id.
110
Id.
111
Id.
24
released.112 The study found that all of the 6 tests were
found to be alcohol sensitive, and the officers made
correct arrest/relaease decisions for 76% of the
participants.113 The study also led to the recommendation
that the best battery of tests would include the one-leg
stand, the walk-and-turn, and the alcohol gaze nystagmus
tests.114
The drinking subjects were recruited through the
California State Employment Officer and were paid $3.00 per
hour for participation in one session.115 The Police Officer
– examiners were recruited from Los Angeles area agencies
and were selected to represent a broad spectrum of
experience with DWI testing.116 Potential drinking subjects
were interviewed and scheduled by telephone.117 The drinking
subjects were instructed to take no food or stimulants for
four hours preceding a session and to abstain from alcohol
for 24 hours.118 Although the study admits that these
conditions were violated by a number of persons, some
arriving with positive BAC’s and several admitting to
112
Id.
Id.
114
Id.
115
Id. at 13.
116
Id.
117
Id. at 15.
118
Id.
113
25
having eaten within the proscribed timed, the violators
were still allowed to participate.119
The primary question of interest was whether the
officers were able to make the correct decision, that is,
to arrest the persons at or above .10% BAC or to not arrest
those below .10% based on test performance.120
The matrix below represents the studies findings:121
The matrix shows that for participants tested with a
BAC equal to greater than .10% the police made the correct
decision to arrest 84% of the time. Participants with BACs
less than .10%, the police made the correct decision to not
arrest 73% of the time. What the matrix seems to hide is
119
Id.
Id. at 25.
121
Id.
120
26
the fact that of the 101 participants that the police said
that they would have arrested, 47 had BACs below .10%.
Furthermore; these results were reached after a 6-test
battery, rather than the 3-test battery normally used
today; and also this 6-test battery was administered in a
laboratory rather than the more difficult field
environment. Another alarming find of this study is that
six people received no alcohol at all but officers still
indicated that they would have arrested them.122
Visual Detection of Driving While Intoxicated, 1980
The National Highway Traffic Safety Administration
contracted another study finalized in 1980. The study was
titled “The Visual Detection of Driving While Intoxicated,
Field Test of Visual Cues and Detection Methods.” This
study was conducted by Anacapa Sciences, Inc. and authored
by Douglas H. Harris.
This study was conducted to answer the following
questions: “What visual cues occur frequently enough to be
useful for DWI Detection; to what extent do different cues
discriminate between DWI and DWS; how can information on
122
Id. at 26.
27
cue occurrence and discriminablility be used best for onthe road detection of DWI?”123
The research was conducted with the help of 10
participating police agencies.124 “Measures related to DWI
enforcement effectiveness were obtained from each agency
during a 12-month baseline period and during a three-month
test period in which the Guide was used.”125 The Guide was a
DWI Detection Guide is shown below:126
123
Harris, Douglas; "The visual Detection of Driving While Intoxicated, Field Test of Visual Cues and
Detection Methods”; Anacapa Sciences, Inc.; Technical Summary (1980).
124
Id.
125
Id.
126
Id.
28
29
The three measures that were obtained during each period
were, DWI arrest rate, frequencies of reported detection
cues, and BAC levels of persons arrested.127
The results of the detection study showed that 39% of
the drivers stopped for suspicion of DWI had a BAC less
than 0.05; 23% had a BAC grater than 0.05 but less than
0.10; and 38% had a BAC equal to or greater then 0.10.128 Of
these stops the following table was created to show the
frequency of occurrence of each cue:129
127
Id.
Harris, Douglas; Visual Detection of Driving While Intoxicated; Anacapa Sciences, Inc. HUMAN
FACTORS, December 1980, 22(6), pg. 727.
129
Id..
128
30
The conclusions drawn from the study by Harris were
that: 1. Although the potential number of visual detection
cues is large, most detection events can be accounted for
by a relatively small number of cues; 2. There are large
differences among visual detection cues in the frequency
31
with which they occur with DWI and in their ability to
distinguish between DWI and DWS; 3. Typically, a visual
detection cue is observed with one or more other cues.
However, there are no subsets of specific cues that occur
frequently together; 4. Except for patrol emphasis, the
conditions under which cues are observed have relatively
little influence on frequency of cue occurrence; 5. The
basis exists for the development and evaluation of a DWI
detection guide to facilitate the application of research
findings to on-the-road detection of DWI by police patrol
officers.130
The data doesn’t seem to make a compelling argument
that these visual cues would indicated an intoxicated
driver.
Development and Field test of Psychophysical Tests for DWI
Arrest, 1981
Burns and Moskowitz conducted another study for NHTSA
in 1981. This study was titled “Development and Field Test
of Psychophysical Tests for DWI Arrest”. For this study,
the administration and scoring procedures for a sobriety
test battery consisting of the walk-and-turn test, the on
leg stand test, and the horizontal gaze nystagmus test were
130
Id. at 728.
32
standardized.131 This meant that all the participants were
instructed to conduct the tests in the same manner and
their performance was scored by the same standards. The
effectiveness of the standardized three-test battery was
then evaluated in the laboratory and to a more limited
extent, in the field.132 Ten police officers administered
the tests in the laboratory to 297 drinking volunteers with
blood alcohol concentrations ranging from 0 to 0.18%.133 The
abstract claims that the officers were able to classify 81%
of these volunteers, on the basis of their test scores,
with respect to whether their BACs were above or below
0.10%.134 It goes on to say that the officer estimates of
the BACs of people they tested differed by 0.03% on the
average from the actual BAC.135 Next the study was continued
in a limited field evaluation where police officers filled
out 3,128 data forms. Each data form represented a driver
stopped during a three month period.136 The final report
claims that after being trained on the test battery the
police officers tended to increase their arrest rates and
131
Tharp, Burns, Moskowitz, “Development and Field Test of Psychophysical Tests for DWI Arrest”; Final
Report, Technical Report abstract, DOT-HS-8-01970 (1981).
132
Id.
133
Id.
134
Id.
135
Id.
136
Id.
33
appeared to be more effective in estimating BACs of stopped
drivers than they were before training.137
Below is the Decision Matrix of Police Officers’
arrest/ no arrest decision in a laboratory environment:138
The table shows that of the 125 participants who had
actual BAC’s greater than .10%; the police officers would
have made the incorrect arrest decision 34% of the time. Of
the 316 participants who had a BAC below .10%; 38 would
have been wrongly arrested. Of the 118 participants that
the officers would have arrested the officers would have
made the correct arrest decision only 68% of the time.
137
138
Id.
Id. at 27.
34
Field Evaluation of a Behavioral Test Battery for DWI, 1983
In September of 1983 the National Highway Traffic
Safety Administration received “Field Evaluation of a
Behavioral Test Battery for DWI” by Theodore Anderson,
Robert Schweitz, and Monroe Snyder. This paper presented
the findings from a field evaluation of the sobriety test
battery.139 The report states that police officers from four
jurisdictions were trained in the use of the sobriety test
battery; and then they administered the battery to drivers
that they stopped for suspicion of driving while
intoxicated during a three month period.140 The study claims
that the test battery could be easily administered in the
field and that it was effective in determining whether a
driver’s Breath Alcohol Concentration was above or below
.10%.141
139
Anderson, Schweitz, Snyder; “Field Evaluation of a Behavioral Test Battery for DWI”; Office of Driver
and Pedestrian Research Problem-Behavior Research Division; pg. 1, (1983).
140
Id.
141
Id.
35
The table below shows the results from the study:142
Validation of the Standardized Field Sobriety Test Battery
at BACs Below 0.10 Percent.
In August of 1998, Jack Stuster and Marcelline Burns
completed a final report on the ability of police officers
to detect BACs below 0.10 percent. This study evaluated the
142
Id. at 11.
36
accuracy of the Standardized Field Sobriety Test Battery to
assist officers in making arrest decisions for DWI at blood
alcohol concentrations (BACs) below 0.10 percent.143 The
original NHTSA SFST battery was validated at 0.10 percent
BAC in 1981.144 In the proceeding years the trend to reduce
the statutory DWI limits to 0.80 percent prompted this
study.145 The
Seven officers of the San Diego Police Department’s
alcohol enforcement unit were trained in the administration
and modified scoring of NHTSA’s SFST battery.146 The SFST
scoring was adjusted in that the observation of four HGN
clues indicated a BAC equal to or greater than 0.08 percent
rather than four clues indicating a BAC equal to or greater
than 0.10 percent.147 During routine patrols, the
participating officers followed study procedures in
administering SFSTs and completing a data collection form
for each test administered and then administered an
evidentiary breath alcohol test.148 Stuster and Burns
maintain that the data analysis found the SFSTs to be
extremely accurate in discriminating between BACs above and
143
Stuster, Burns; “Validation of the Standardized Field Sobriety Test Battery at BACs Below 0.10
Percent”; U.S. Department of Transportation, National Highway Traffic Safety Administration; Anacapa
Sciences, Inc.; Technical Report Documentation Page; (1998).
144
Id.
145
Id.
146
Id.
147
Id.
148
Id.
37
below 0.08 percent.149 They also found that the HGN test was
the most predictive of the three components of the SFST
battery, however a higher correlation was obtained when the
results of all three tests were combined.150
The decision analysis also found that officers’
estimates of whether a motorist’s BAC was above of below
0.08 or 0.04 percent were extremely accurate.151 Stuster and
Burns say that estimates at the 0.08 level were accurate in
91 percent of the cases and that officers estimates of
whether a motorist’s BAC was above 0.04 percent but lower
than 0.08 percent were accurate in 94 percent of the
decisions to arrest and in 80 percent of cases overall.152
Stuster and Burns conclude their study by finding that
the results of this study provide clear evidence of the
validity of the Standardized Field Sobriety Test Battery to
discriminate at 0.80 percent BAC, using a slightly modified
Scoring procedure.153
WHAT THE CRITICS SAY
149
Id.
Id.
151
Id.
152
Id.
153
Id.
150
38
The critics of the NHTSA protocol for DWI Detection
are extensive and vocal. The remainder of this paper will
take a look at some of these criticisms.
CRITICISMS OF PHASE 1 AND 2
Alcohol breath odor is one of the most frequently
cited observations that police officers make in alcohol
related traffic offenses.154 However; a NHTSA study shows
that alcohol breath odor is only detectable, with any
degree of accuracy, at very high BAC levels. The National
Highway Transportation Safety Administration conducted a
pilot study examining cues utilized by officers in
detecting drivers under the influence of alcohol in 1985.155
In this study, 75 male volunteer drivers were given
alcoholic beverages sufficient to produce BACs of either
zero or between 0.05 and 0.15%.156 Consumption was spaced
over a 1.5-2 hour period, after an additional half hour
wait, the subjects drove a car over a closed course to a
check point where the officer/observer conversed with the
driver. The officer was tasked with noting whether alcohol
odor was present, and whether the suspect’s face was flush,
speech was slurred, eyes were dilated, hair or clothes were
154
Moskowitz, Burns, & Ferguson; “Police officers’ detection of breath odors from alcohol ingestion”
Accident Analysis and Preventtion 31; pg. 175 (1999).
155
Id. at 176.
156
Id.
39
disheveled or had poor dexterity.157 The officer then made
the determination of whether the driver should be detained
for further investigation.158 There were 7% false-positives
(i.e. identification of a zero BAC driver as having alcohol
odor) with drivers who had a zero BAC.159 An alcohol odor
was detected in drivers with BACs between 0.05 and 0.09%
only 39% of the time, and detection of an alcohol odor on
drivers with BACs above 0.10 only occurred 61% of the
time.160
The results of this study seem to show that odor
of alcohol is an extremely poor indicator of intoxication.
A different study was done by a research group from
the University of Utah to compare the cell phone driver
with the drunk driver. The study used a high-fidelity
driving simulator to compare the performance of cell-phone
drivers with drivers who were legally intoxicated, from
ethanol.161 The researchers found that when drivers were
conversing on either a hand-held or hands-free cell-phone,
their braking reactions were delayed and they were involved
in more traffic accidents than when they were not
157
Id.
Id.
159
Id.
160
Id.
161
Strayer, Drews, Crouch; “A Camparison of the Cell Phone Driver and the Drunk Driver”; Joint Center,
AEI- Brookings Joint Center for Regulatory Studies; Working Paper 04-13, Executive Summary, July
2004.
158
40
conversing on the cell phone.162 The researchers also found
that when drivers were legally intoxicated they exhibited a
more aggressive driving style, following closer to the
vehicle immediately in front of them and applying more
force while braking.163 The most interesting thing that the
researchers found was that when controlling for driving
conditions and time on task, cell-phone drivers exhibited
greater impairment than intoxicated drivers.164
This study was conducted with forty-one participants.
The participants had their driving skills tested on a
driving simulator while either talking on a cell phone, or
with a BAC equal to 0.08%.165 In the alcohol session, the
participants drank a mixture of orange juice and vodka
calculated to achieve a blood alcohol concentration of
0.08%.166 Then the participants had their BAC verified using
an infrared spectrometry immediately before and after the
alcohol driving condition.167 The participants then drove a
car-following scenario, while legally intoxicated.168 In the
cell-phone session, three counterbalanced conditions were
included: single-task baseline driving, driving while
162
Id.
Id.
164
Id.
165
Id. at 4.
166
Id.
167
Id.
168
Id.
163
41
conversing on a hand-held phone, and driving while
conversing on a hands-free cell phone.169 In both cell-phone
conditions, the call was initiated before the participants
began driving to minimize interference from the manual
components of cell phone use.170
The
researchers found that when participants in the
simulation were conversing on a cell-phone, they were
involved in more rear-end collisions, their initial
reaction to vehicles braking in front of them was slowed by
8.8%, and the variability in following distance increased
by 24.5%, relative to baseline.171 Furthermore, it took
participants who were talking on the cell phone 14.8%
longer to recover the speed that was lost during braking.172
Remarkably, researchers found that when participants
were legally intoxicated, neither accident rates, nor
reaction to vehicles braking in front of the participant,
nor recovery of lost speed following braking differed
significantly from the baseline.173
I chose to introduce this study here not to show that
driving while intoxicated is not dangerous; but show that
the clues of impairment that officers are instructed to
169
Id.
Id.
171
Id. at 6.
172
Id.
173
Id.
170
42
look for during phase one and two are not founded in fact.
Many of the clues that the NHTSA manual teaches are not
indicators of an intoxicated driver, but indicators of a
distracted driver. In being so, it seems unduly prejudicial
for such observations to be offered as evidence of
intoxication in Court.
CRITICISMS OF PHASE 3
Field Sobriety Tests: Are They Designed For Failure?
Spurgeon Cole and Ronald Nowaczyk reexamined the
studies done for NHTSA, discussed earlier in this paper.
Cole and Nowaczyk point out that in the 1977 study, 47
percent of subjects who would have been arrested based on
test performance actually had a blood alcohol concentration
lower than .10 percent.174 In 1981, when standardized field
sobriety tests were again tested for use by the NHTSA, the
study found that 32% of the participants were incorrectly
judged to have BACs greater than .10.175
Cole and Nowaczyk state that the reliability
coefficients for these tests were often below accepted
174
Cole, Nowaczyk; “Field Sobriety Tests: Are They Designed For Failure?”; Perceptual and Motor Skills,
99-104 pg 100 1994.
175
Id.
43
levels for standardized clinical tests.176 They reason that
the problems in scoring can be attributed, in part, to the
lack of standardization across any of the field sobriety
test studies.177 Furthermore, a few miscues in the
performance of any of the field sobriety tests by a
participant could result in that participant being scored
as impaired.178 The example that they give is that a person
is viewed as impaired for missing two of nine points on the
walk-and-turn test or two of five points on the one-leg
stand.179
Coles and Nowaczyk conducted a study where 14 police
officers rated the performance of 21 participants who had
completed the field sobriety and normal-abilities tests on
videotape.180 The participants were recruited from local
businesses, aged between 21 and 55 and were not overweight
nor had any know physical disabilities.181 Prior to the
administration of the tests, each participant was
administered the datamaster breathalyzer test and all had a
BAC level of 0.00.182 Each participant performed six field
sobriety tests and four normal-abilities tests in the same
176
Id.
Id.
178
Id.
179
Id.
180
Id. at 101
181
Id.
182
Id.
177
44
order in an indoor setting.183 The field sobriety tests
included the walk-and-turn test, alphabet recitation, oneleg stand, a one-leg stand while tilting backward with the
eyes closed and touching the nose, a one-leg stand while
counting, and a one-leg extension test.184 The four normalabilities tests included counting from 1 to 10, reciting
one’s Social Security number, driver’s license number or
date of birth, reciting one’s home address and phone
number, and walking in a normal manner, turning around, and
walking back to the starting point.185
Each officer watched a videotape of the 21 individuals
performing one of the two sets of tests and were asked “do
you feel as a law enforcement officer, that the following
subjects, based on field sobriety tests performed on
videotape, have had too much to drink to drive.”186 Their
responses, either yes or no, were recorded for each
individual.187
The officers’ decisions were that 46% of the
participants had too much to drink from viewing the field
sobriety tests.188 The normal-abilities test’s resulted in
the officer’s believing that 15% of the participants had
183
Id.
Id.
185
Id. at 101-102.
186
Id. at 102.
187
Id.
188
Id.
184
45
too much to drink.189 Cole and Nowaczyk state that the data
indicates that an individual was more likely to be judged
as impaired on the basis of field sobriety test performance
than on performance of the normal abilities tests.190 Even
without alcohol, the number of errors made by individuals
performing the field sobriety tests was sufficient for
officers to judge that the individuals had too much to
drink.191
Again the results of this study call into question the
legitimacy of Courts allowing field sobriety testing as
evidence of impairment. “The tests should discriminate
between the two populations of individuals who are impaired
and those who are not.”192
A similar study; done by Terry and Ruth Martinez of
Toxicologic Associates Inc., found even more troubling
results. The study was titled, “Failure of Standardized
Psychophysical Tests for DWI to distinguish Between Blood
Alcohol Levels of 0.000 and 0.080 to 0.125”. The study
consisted of 14 adult volunteers who had been arrested
previously for driving under the influence.193 Breathalyzer
189
Id.
Id. at 103
191
Id.
192
Id.
193
Martinez, Martinez; Failure of Standardized Psychophysical Tests for DWI to Distinguish Between
Blood Alcohol Levels of 0.000 and 0.08 to 0.125 G/DL, Proc. West. Pharmacol. Soc. 46: 170-173, pg 170
(2003).
190
46
tests at the police stations reported blood alcohol
concentrations to be between 0.080 and 0.125 g/dl.194
Martinez states that this puts the subjects into a
borderline legal limit range for blood alcohol and were
referred by their attorneys for evaluation.195
As part of this evaluation they were given repeat
road-side sobriety tests to verify the criteria used by the
police officer.196 Field Sobriety testing at the time of the
arrest was conducted by police officers trained to National
Highway Traffic and Safety Administration standards and all
laboratory tests were administered by an investigator who
had completed a course in those same standards.197 The same
standards were used because as the NHTSA manual suggests;
the validity of field sobriety test applies only when the
tests are administered in the prescribed, standardized
manner; when the standardized clues are used to assess the
suspect’s performance; and when the standardized criteria
are employed to interpret that performance.
The study showed that the participants scored 0-5
clues of impairment when they were intoxicated with a mean
of 2.6 for the walk and turn test.198 Non-drinking
194
Id.
Id.
196
Id.
197
Id.
198
Id. at 171.
195
47
participants had a range of 0-6 clues with a mean of 2.5.199
Six of the subjects scored more clues of impairment when
they were intoxicated, six scored higher when they were
sober, and there were two ties.200
The one leg stand test showed a range of 0 to 4 clues
of impairment scored for drinking subjects with a mean of
2.1. Non-drinking subjects had a range of 0-4 clues of
impairment scored with a mean of 1.2.201 In seven cases the
subjects scored higher in the drinking situation and in one
case the subject scored higher on this test when he had not
been drinking.202 In six cases the results were the same
regardless if the subject had been drinking or not.203
The horizontal gaze nystagmus test had a range for 4
to 6 clues in the drinking subjects with a mean of 5.1.204
Non-drinking subjects had a range of 2 to 6 with a mean of
3.9.205 In eleven cases, the subjects scored higher in the
drinking situation, compared to two cases where the result
was higher when not drinking, while in one case the results
were the same.206 The difference between drinking and non
drinking subjects was not clinically significant; however,
199
Id.
Id.
201
Id.
202
Id.
203
Id.
204
Id.
205
Id.
206
Id.
200
48
because ten out of the fourteen subjects showed four or
more clues with no alcohol in their systems and would still
have failed this test even before they started drinking.207
“Cases and literature indicate that, in addition to
alcohol, many other factors have been mentioned as a
possible cause of nystagmus.”208 They include: 1. problems
with the inner ear labyrinth; 2. irrigating the ears with
warm or cold water under peculiar weather conditions; 3.
influenza; 4. streptococcus infection; 5. vertigo; 6.
measles; 7. syphilis; 8. arteriosclerosis; 9. muscular
dystrophy; 10. multiple sclerosis; 11. Korchaff’s syndrome;
12. brain hemorrhage; 13. epilepsy; 14. hypertension; 15.
motion sickness; 16. sunstroke; 17. eye strain; 18. eye
muscle fatigue; 19. glaucoma; 20. changes in atmospheric
pressure; 21. consumption of excessive amounts of caffeine;
22. excessive exposure to nicotine; 23. aspirin; 24.
circadian rhythms; 25. acute trauma to the head; 26.
chronic trauma to the head; 27. some prescription drugs,
tranquilizers, pain medications, anti-convulsants; 28.
barbiturates; 29. disorders of the vestibular apparatus and
brain stem; 30. cerebellum dysfunction; 31. heredity; 32.
diet; 33. toxins; 34. extreme solvents, dry cleaning fumes,
207
208
Id.
Schultz v. State, 106 Md. App. 145 at 180 (Md. App. 1995).
49
carbon monoxide; 35. extreme chilling; 36. eye muscle
imbalance; 37. lesions; 38. continuous movement of the
visual field past the eyes, i.e., looking from a moving
train; 39. antihistamine use.209
Criticism of the 1998 Study: Validation of the Standardized
Field Sobriety Test Battery at BACs Below 0.10 Percent
Michael Hlastala, Nayak Polissar and Steven Oberman;
took reanalyzed the research that was done for NHTSA. In
particular they looked at a study done in 1998 entitled
“Validation of the Standardized Field Sobriety Test Battery
at BACs below 0.10 Percent.” After reviewing the data
compiled back in 1998, the research team made some
insightful observations. They found that the accuracy of
the SFST is not a single percentage, but depends on the
level of the measured BAC.210 The data showed that if the
measured BAC is lower than 0.04 percent, the officer is
generally 80 percent or more accurate at predicting the
subjects category (above or below 0.08 percent).211 If the
measured BAC is greater than 0.09 percent, then the officer
is about 90 percent or more accurate at predicting the
209
Id.
Hlastala, Polissar, Oberman; “Statistical Evaluation of Standardized Field Sobriety Tests” J Forensic
Sci, May 2005, Vol. 50, No. 3; pg. 2 (2005).
211
Id.
210
50
subject’s category.212 However, if the measured BAC is
around 0.08 percent, specifically, between 0.06 and 0.08
percent, the SFSTs are only about 30-60 percent accurate in
correctly predicting whether a subject’s measured BAC was
above or below 0.08 percent.213
Hlastala, Polissar and Oberman also found that the
data provides evidence that the officers’ estimates were
not based only on the SFST.214 They used an analysis where
even a very liberal use of only the SFST in a predictive
model yields a BAC estimate with precision that is
substantially inferior to the precision of the officers’
estimates, even though the officers were instructed to base
their estimates only on the SFST.215 The striking increase
in precision when the officer estimates are added to a
liberally-fitted model using only the tests suggests that
the officers did not base their estimate solely on the test
scores but most likely used other clues such as using
portable breath testers prior to recording their BAC
estimates.216
Conclusion
212
Id.
Id.
214
Id. at 3.
215
Id. at 2.
216
Id.
213
51
The Standardized Field Sobriety Test Battery has been
around for many years and so have the criticisms of that
battery. The studies used to validate field sobriety
testing are questionable at best. A better system needs to
be put in place, or judges and juries need to be made aware
of the problems with the Standardized Field Sobriety Test
Battery so that they don’t lend the results of these
“tests” more evidentiary value then they deserve. More
importantly, police officers need to be taught the problems
and shortcomings of the Standardized Field Sobriety Test
Battery so that arrests will be based off of facts rather
than speculation or voodoo science.
52