Dallas DWI Attorney

Texas FIELD SOBRIETY TESTS for
DWI

There are 3 "standardized" tests that police
officers give in order to determine if they have
probable cause to arrest a person for DWI.
They also give other tests, but they are not
the "standardized" tests. The three tests are
1) the HGN (Horizontal Gaze Nystagmus
test), 2) the Walk and Turn, and 3) the One
Leg Stand.

1) HGN: Horizontal Gaze Nystagmus.   This
test is used to see if your eyes jerk
involuntarily when following an object. The
police are trained that if a person's eyes do
exhibit this jerk (nystagmus), this is a sign of
intoxication. The test must be administered
properly to obtain an valid result.

2) Walk and Turn:   This test is designed to
evaluate the subjects mental and physical
faculties. You are given a series of
instructions, and if you vary from the
instructions, police are trained to use these
deviations from the instructions as evidence
of intoxication. The instructions you are
given are to do a physical task (basically,
walk the straight line, turn and walk back). It
sounds simple, but the instructions are
designed to make this a very unnatural type
of walk. If you are unable to walk and turn in
exactly the way the officer asks you to walk
and turn, the officer is trained to see this as
evidence of intoxication.

3) One Leg Stand : This is a similar test to
the Walk and Turn, in that it has a physical
and mental portion. They test your mental
faculties by once again, seeing if you can
follow their directions. They test your
physical faculties by observing whether you
can actually perform the test. On the
physical part of the exam, they look for
swaying, using arms for balance, hopping,
placing a foot down before 30 seconds
expire. Unfortunately for the test subjects,
they are not told that they will be graded off
for these things.