How Does a DUI Defense Attorney Attack the Field Sobriety Tests?

It is important to recognize that the Field Sobriety Tests (FSTS) are incredibly unreliable.  As a matter of fact, in most cases the officer testifying who administered the FSTS will have absolutely no idea what these tests mean.  For instance, here are a couple of sample questions I might ask an officer on the witness stand, “Officer Jones what do these tests mean as far as giving us a percentage that someone is under the influence of alcohol?  Do they mean that if someone fails these tests that there is a 50% chance they are under the influence or do they mean there is a 75% chance they are under the influence?  Most likely the response will go, “uh..duh..I don’t know.”  And my response is, “well if you don’t know, how is the jury supposed to know!” 

In fact the National Highway Traffic Safety Administration (NHTSA) instructs officers to stay away from discussing the numerical significance of field sobriety tests.  They tell officers to avoid this topic because the numerical significance based on NHTSA is wide open to misinterpretation.

Some courts have held that if field sobriety tests are not administered correctly, they are inadmissible.  The Ohio State Supreme Court held in Ohio v. Homan, 732 N.E.2d 952 (Ohio 2000), that field sobriety tests conducted in a manner that deviates from NHTSA protocol are unreliable and should be inadmissible.   While this is not a California case, its reasoning can be applied in front of a California jury.  

Only three FSTS are approved by the National Highway Traffic Safety Administration (NHTSA) these tests are Horizontal Gaze Nystagmus (HGN), the walk-and-turn, and the one-leg stand.  All of these tests are voluntary.  There is no legal requirement to participate in these tests.  When you drive a car, you impliedly consent to give a chemical test, blood, breath or urine.  There is no requirement that you subject yourself to the FSTS.

Horizontal Gaze Nystagmus (HGN)

(HGN) is where the eyeball involuntarily jumps as a person gazes from side to side.   Under normal circumstance, everone’s eye jumps to some degree when they gaze from side to side and when the eye reaches a 45 degree angle.  However, alcohol or drugs may enhance this condition.   To perform this test, the officer will slowly move a pen or flashlight and observe the eye.  The officer is looking for three things, (1) the eye does not track smoothly (2) the eye jerking is distinct at 45 degrees (3) the jerking starts before 45 degrees.  If the officers sees 4 or more of these symptoms between the two eyes, according to the NHTSA there is a 77 percent chance that the subject has a blood alcohol concentration (BAC) of .10 percent or more.  According to the NHTSA, this test may also indicate the consumption of other illegal or prescription drugs as well.  This test which is 77% accurate, and that’s if you believe that number, is the most accurate of all the FSTS!  There are approximately 40 known causes of nystagmus.  These phenomena were described in detail in the case of v. Horn (2002) 185 F.Supp.2d 530.  Other causes of nystagmus are diet, heredity, fatigue, eyestrain, multiple sclerosis and influenza (flu).  This is just a partial list.  Even consumption of aspirin, caffeine or nicotine could lead to a false positive HGN test! 

 Walk-and-Turn

For the walk-and-turn test, the driver takes nine steps, heel-to-toe, in a straight line. The driver turns on one foot and walks the line in the opposite direction. The officer looks for seven clues that a driver is under the influence: (1) driver cannot keep his balance during the instructions (2) begins the test before the officer finishes the instructions (3) stops walking (4) does not walk heel-to-toe (5) cannot keep his arms to his sides (6) loses balance during the turn (7) takes more or less than nine steps on either the outbound or inbound walk. The NHTSA claims that 68 percent of people who show two clues or more while have a BAC of 0.10 or greater.

 One-Leg Stand

This requires that the driver to stand on one foot and count until told to put the foot down. The test lasts 30 seconds.  During this time, the officer looks for four clues that a driver is under the influence: (1) using arms to balance (2) swaying (3) hopping to maintain balance (4) touching the ground with the foot putting the foot down.  The NHTSA claims that 65 percent of people who show two or more clues during the test the will have a BAC of 0.10 of greater.

Both the Walk-and-Turn and the One-Leg Stand tests may be effected by physiological factors.  For instance, if the driver suffers from a physical ailment or is elderly these tests will be compromised and are not reliable.  For these tests to be administered accurately the subject must be a healthy individual.  These tests should only be done on a dry, hard, level, non-slippery surface and should be done in an area with adequate lighting.

  Non-Standardized Field Sobriety Tests

Only the Horizontal Gaze Nystagmus (HGN), Walk-and-Turn and One-Leg Stand tests are approved by the National Highway Traffic Safety Administration (NHTSA), all other testing procedures are non-standardized tests that hold less weight in court. 

These non-standardized tests may include reciting the alphabet, the finger-to-nose test, the finger dexterity test, and the hand-pat test.  The Rhomberg balance test is a commonly used non-standardized test.  The Rhomberg balance test requires a person to stand with his feet together, tilt his had backwards and close his eyes.  The subject must stay in that position and estimate when 30 seconds have elapsed.  The person is required to estimate hen 30 seconds are up, open his eyes, tilt his head forward and tell the officer “stop.”

The subject fails the test by under or overestimating the passage of time, by not following directions or by swaying.  The Rhomberg test as well as other non-standardized tests are not approved by the NHTSA.  A DUI defense attorney can attack the use of these tests, since they are not reliable.  These non-standardized tests have not been approved for use in the scientific or medical field to determine impairment.  The NHTSA actually discourages officers from using these tests unless there is some reason the standardized tests could not be performed.  The NHTSA advises that an officer note in his report why he could not use the standardized tests.  Despite this advice, many officers use non-standardized tests.  A resourceful DUI lawyer can turn this to your advantage by questioning the officer on his failure to administer nationally approved field sobriety tests.

The Law Office of Michael E. Mitchell defends clients charged with DUI / DWI and traffic offenses in California's Central Valley and San Joaquin Valley, including Fresno County, Tulare County, Merced County, Madera County, County of Kings, Mariposa County, Fresno, Tulare, Merced, Madera, Kings County, Mariposa, Visalia, Hanford, Dinuba, Los Banos, Selma, Kingsburg, Clovis, Sanger, Reedley, Kerman, Parlier, Coalinga, Firebaugh, Fowler, Mendota, Visalia, Avenal, Corcoran, Lemoore and Lemoore Naval Air Station (NAS), Porterville, Bass Lake, Shaver Lake, Millerton Lake, Hensley Lake, Pine Flat Lake, Yosemite National Park, Sequoia National Park.  We also defend motorists pulled over for traffic violations along San Joaquins roads and highways including interstate 5 and highways, 49, 41, 99, 168, 192, 180.