Field Sobriety Tests

What you should know about Field Sobriety Tests.

Field sobriety tests are not mandatory and you do not have to perform them if stopped by police.  Most people are not aware of this, so its important to repeat: YOU DO NOT have to perform field sobriety tests if you are stopped for suspicion of DUI.  (If you are on probation, you may have to perform these tests.)  Field sobriety tests involve a battery of tests “designed” DUI Field Sobriety Tests(and I used that term loosely) to determine if you are impaired by alcohol.  These tests ostensibly test ability to listen and understand instructions, balance, perception, ability to divide tasks and multi-task, and the ability to estimate time accurately.  It is thought that all of these abilities would be effected if a person was impaired by alcohol.

What happens during Field Sobriety Tests.

All of the field sobriety tests used by law enforcement have at least two parts: The instruction phase and the performance phase.  During the “instruction phase” the law enforcement officer will read to you the instructions.  It may seem like the officer is speaking fast during the instructions: that is because it is.  One of the sneaky things law enforcement does during the instructions is go through the instructions quickly to see if you trip up.   They will later use any misunderstandings of these instructions as “proof” that you were too impaired to understand the instructions.  I always advise clients to not perform FST’s (Field sobriety tests), but if they do, do not let law enforcement read them too quickly so the client doesn’t understand.  Make sure you understand the tests if you are going to perform them, and look out for officers reading or going over the tests too quickly for you to understand. The second part of the tests is the performance phase. During the performance phase, the driver is monitored by police to see if they can perform the tests as instructed.  The officer is looking for a number of things: -Ability to perform the test as instructed -Balance -Coordination -Physiological clues, such as movement of the eyes or eye-lids -Sense of time

Field Sobriety Test Resource Links:
National Highway Traffic Safety Administration FST link
CHP Drug Recognition Program

What are the different Field Sobriety Tests that law enforcement use?

The most common field sobriety tests are:
-Walk the line (heel/toe) test
-Stand on one leg test
-Horizontal Gaze Nystagmus test
-Rhromberg test

Walk the line (heel/toe)

The Walk the line test is a test that looks at the driver’s balance, coordination, ability to remember instructions, ability to multi-task.  In the test, the instructions are given (remember, officers will often go over the instructions purposely fast to trip the driver up.) where the driver is instructed to walk with their arms to their sides, stepping with the heel of their advancing foot touching the toe of the other foot as they progress.  The driver will be instructed to walk 9 steps forward, pivot on one foot, and walk 9 steps back, counting out loud and keeping their head down looking at their feet. During the test, officers look to see if the driver raises their arms to help balance themselves.  This is not allowed.  Also watched for by the officers is the driver’s ability to track the “invisible line” that they walk along, as well as their ability to count the correct number of steps.  The officer will also look for the driver not pivoting on one foot as instructed.  As will all Field Sobriety Tests, it is advisable you refuse to perform this test if asked to perform it by police.

Stand on one leg test

The stand on one leg test is the ultimate test of balance, which should present a problem for someone who has had too much to drink.  As with the other Field Sobriety Tests, it is advisable that you refuse to perform the test before it even starts.  If you do perform the test, look out for the police officer quickly going over the instructions.   During the test, you will be asked to sand on one leg, with your arms down to your sides, while counting “30 seconds” out loud.   The driver will be instructed to look down while performing the test, and will be monitored for the following mistakes: -reaching out with the arms to assist balance -mis-counting or counting longer or shorter than 30 seconds. (An impaired driver will often count 30 seconds more slowly than a sober driver, and will actually take 50 or more seconds while counting the 30 seconds out-loud.) -putting the raised foot down briefly to assist balance

Horizontal Gaze Nystagmus Test

During the horizontal nystagmus test, the driver is instructed to stand errect, with their arms to their sides.  If the driver sways, or reaches out with their arms to assist balance, the police officer will use that against the driver as proof of impairment. The officer will use a finger, or a pen or similar object, and instruct the driver to track the movement of the object with their eyes.  During the slow movement of the object, as the driver attempts to track the object with their eyes, the police officer is looking for tell-tale signs of impairment.  If a driver is impaired, their eye will not “smoothly.”    An impaired person’s eyeball will twitch as they attempt to track the movement of the object because of alcohol’s influence on the muscles of the eye.

Rhomberg Test

The Rhomberg test is as strange test, where the driver is instructed to stand with their head tilted back, arms straight down by their sides, eyes closed, and estimate (not count) the elapsing of 30 seconds.  An impaired driver will often sway back and forth, extend their arms for balance, and or mis-estimate the elapse of 30 seconds.  (For example, some drivers have estimated over 1 minute while attempting to estimate 30 seconds during this test because alcohol slows down the mental functions and bio-rythyms of an impaired person.)

What you should do if asked to perform these Field Sobriety Tests.

Assuming you are not on DUI probation, you should refuse to perform these tests.  They are never a good idea for a driver to perform, and only give police more “evidence” against a driver.

Updated January 13, 2014 by Jon Straub.

Posted in DUI Lawyer.

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