standardized field sobriety tests
July 2, 1997, the BAC (blood alcohol content) limit for the
state of Illinois was lowered to 0.08.
The National Highway
Transportation Safety Administration (NHTSA) has developed
three standardized field sobriety tests to assist officers
in determining whether or not one suspected of DUI has a
blood alcohol content in excess of .08 percent. The three
Field Sobriety Tests (FSTís) are the Horizontal Gaze
Nystagmus (HGN), the nine-step walk and turn, and the one
leg stand. The nine-step walk-and-turn and the one-leg stand
tests are considered "divided attention tests" because they
test both a suspectís coordination and the ability to
remember and process information. Driving is a complex task
that requires clear vision, focus, short-term memory
ability, coordination, fine motor control, judgment, and
decision-making. When a person is under the influence of
alcohol, these abilities may be impaired.
1) Horizontal Gaze
Nystagmus (HGN) Test
Nystagmus is a medical term describing the involuntary
jerking of the eyes. An officer instructs a suspect to
follow his or her pen, with only the eyes, as he or she
moves the pen from side to side across the suspectís
field of vision. The officer instructs the suspect not
to move his or her head, and to follow the pen only with
the eyes. As the officer moves the pen from side to
side, the officer watches the suspectís eye movement.
The officer observes whether or not the suspectís eyes
jerk involuntarily. According to the NHTSA, alcohol may
cause this involuntary jerking.
There are three phases to the HGN test to detect this
involuntary jerking of the eyes. In the first phase of
the HGN test, the officer will hold and move the pen
12-14 inches from the suspectís face, from right to left.
The officer observes the suspectís eyes to determine whether
or not the eyes move smoothly. If the suspectís eyes do not
move smoothly, the officer will record this as "Lack of
In the second phase of the HGN test, the officer moves
the pen to the far end of the suspectís peripheral
vision. Once a suspectís eyes can move no further, the
officer is to hold the pen in that position for at least
four seconds. The officer then observes the suspectís
eyes to determine whether the suspectís eyes remain
still or jerk in a pronounced manner. If the officer
observes a pronounced jerking motion, the officer will
record this as "Distinct Nystagmus at Maximum
In the third phase of the HGN test, the officer moves
his or her pen slowly from the center to the side of the
suspectís face. If the suspectís eyes begin to jerk
prior to the officer reaching a forty-five degree angle
from the center, the officer will record this as "Onset
of Nystagmus Prior to Forty-Five Degrees."
2) Nine-Step Walk and
The nine-step walk and
turn test tests a suspectís coordination and ability to
comprehend and remember information. The first part of
the test is instructional; the second is performance.
The officer first instructs the suspect to place his or
her right foot in front of the left foot, touching
heel-to-toe. The officer should instruct the suspect to
remain in that position until receiving instruction to
begin. The officer instructs the suspect how to perform
the test, and observes to determine if the suspect is
able to maintain his or her balance while receiving
instructions. The officer will record if the suspect
begins the test too soon.
While the suspect performs the test, the officer
observes to determine whether or not the suspect follows
instructions and whether or not the suspect is able to
maintain his or her balance while walking a straight
line. The officer will record if the suspect: misses
heel-toe-while walking the straight line, fails to walk
the straight line, uses his or her arms for balance,
stops, takes the wrong number of steps, or turns in a
manner other than what the officer directed.
3) One Leg Stand Test
The one leg stand
tests a suspectís coordination and ability to comprehend
instructions. The officer directs the suspect to raise
whichever leg the suspect chooses, approximately six
inches from the ground, with the toe pointed straight.
The officer directs the suspect to hold the position,
remaining balanced with arms down at the suspectís
sides. The officer directs the suspect to count, "one
one-thousand," "two one-thousand," "three-one thousand"
etc. & etc., usually to the count of thirty. The officer
will record if the suspect hops, sways, uses his or her
arms for balance, or places his or her foot down before
the count of thirty.
Experience counts. Results matter.
FRANKS & RECHENBERG, P.C.
1301 Pyott Road, Suite 200
Lake in the Hills, IL 60156
DISCLAIMER: This site contains
general information that is intended, but not guaranteed, to be
correct, complete and up-to-date. It is not intended to be a
source of legal advice. You should not rely on the information
in this site and should always seek the advice of a competent
Franks & Rechenberg, P.C. handles
DeKalb County DUI (Driving Under the Influence) charges.