You must understand why the cop wants you to take the
field sobriety tests.  Field sobriety tests are a series of
physical and mental tests the cop gives a driver
to
establish probable cause
for arrest. That is, the sole
purpose of the tests is to give the cop reason to arrest you,
and to help the cop prove that you were driving drunk.  

Look at it this way: let's say the cop stops you for
speeding.  He comes over to the car, and asks for your
license and registration.  He can smell the alcohol on your
breath, your eyes are glassy and bloodshot, and your
speech is slurred a little (that's right, you just
had to start
talking to the cop: "what'd I do, officer?" or "I wasn't
doin' nothin' ").  If that were all that was needed to arrest
you, he would just do it.  But it's not.  He needs more
evidence.  So he asks you whether you have been
drinking.  You say "yes officer, I had two beers."  Guess
what, you just confessed to drinking and then driving.  
Still not enough, but it will be used against you in court.  
Now the cop tells you to get out of the car, which you
must do.  He may have observed you stumble or sway
while you were getting out of the car.  Still not enough
evidence, or he would quit.  Now he "asks" you to do the
field sobriety tests.  You are at a cross roads.  You are not
required to do it, but you feel compelled to do it by the
way the cop told you to do it. But by doing it you give the
cop documented evidence of your level of intoxication (he
fills out a form showing how well you did on the test) that
the judges give great weight to.  

But these tests are humiliating and difficult to do even
while sober.  Some of the tests are:

  • The one-leg stand or the walk and turn, designed to
    test your balance and ability to follow verbal
    directions.

  • Alphabet or counting tests to determine whether you
    can think straight enough to count backwards or to
    recite the alphabet starting in the middle.

  • The horizontal gaze nystagmus test (HGN), a
    physiological test to detect intoxication by tracking
    telltale fluttering while your eyes follow a pen or
    other object.

If you
arrested for drunk driving, you must take the breath
test or lose your license for several months, and possibly
be more severely punished.
But you are not required to do
the field sobriety tests
, and there is a good argument for
politely
refusing to take them. They only serve to provide
evidence against you.
And they may be the only evidence
against you, other than the cop smelling alcohol, noting
red and glassy eyes, or slurred speech (which will always
be in the cop's report).

The field sobriety tests are based on junk science. The
observations of the officer with respect to how you did on
these "tests" are admissible in court and, although the cop
can't testify that you "passed" or "failed," they can testify
as to what they saw you do, and is taken as God's own
truth by the judge.

If you do submit to the tests, they can be challenged in
court. To be meaningful, the tests must be properly
administered. Most cops are trained to use them, but they
do not always do it right. Also, the conditions of the road,
whether it was day or night, wet or dry, may have a
bearing on the validity of the tests.  Also, if you have any
physical impairment that might make it difficult for you to
perform the tests would be an explanation of poor
performance. Your lawyer will know how to bring these
things up and be able to cross-examine the cop to see
whether he is qualified, and whether he did it right.

Once the officer has determined that you may be
intoxicated you will be arrested and taken to the station
for the purpose of taking a
breath test.
The Client
Comes First
Willis & Henderson, P.A.
Attorneys at Law
3290 North Ridge Road
Suite 210
Ellicott City, MD 21043

410-461-9400
DUI/DWI: The Field Sobriety Test