Field Sobriety Tests

Field Sobriety Tests are a name given to a group of tests, mainly physical coordination tasks, that are given to individuals suspected of Driving Under the Influence of alcohol or drugs by the police, prior to arrest. They are considered an investigation tool and, as such, they are VOLUNTARY, unless you are on probation for a prior offense and ordered to complete them. The police will not tell you they are voluntary and will often try to bully or threaten you into doing them. DON’T DO ANY FIELD SOBRIETY TESTS UNLESS YOU’RE ON PROBATION FOR A PRIOR OFFENSE.

Field sobriety tests often also include a preliminary breath test (PBT), most often referred to as a PAS (preliminary alcohol screen) in Monterey County. The only time you are required to take ANY test is after you’re arrested. NO CUFFS = NO TESTS!

There are three tests that are referred to as Standardized Field Sobriety Tests (SFSTs). These tests are approved by the National Highway Transportation Safety Administration or NHTSA (pronounced nitsa). Their claim is that these tests are “validated” by certain field studies and that when these tests are properly administered in a standardized manner and properly evaluated in a standardized manner, they are effective, a certain percentage of the time, in evaluating impairment for purposes of driving. This is only their claim and did they have never been accepted by any peer-reviewed scientific journal as valid. Nonetheless they are commonly given, although not so often correctly given or correctly evaluated.

These three SFST’s are:

  1. The Horizontal Gaze Nystagmus test (HGN). This test is the most commonly given of the three, and sometimes given in conjunction with the other two SFSTs and sometimes in conjunction with non-standardized FST’s (which are worse than useless). This is the test where the cop moves a finger, pen or flashlight in front of your eyes, back and forth, looking for an involuntary jerking of the eyes, referred to as nystagmus. To administer this test correctly, they must first have you remove any glasses, instruct you correctly to keep your head still and move only your eyes, they must position their finger or pencil, etc. 12 to 15 inches from the tip of your nose slightly above eye level, check to see that the eyes have equal pupil size and no resting nystagmus (before the eyes move), then see that both eyes trackside decide equally and only then make a smooth movement from the center of the nose to a maximum deviation (as far as your eyes will move in one direction) then back to center in approximately 2 seconds. They must check your left eye first, then you’re right. They must keep your eye at maximum deviation for a minimum of four seconds.. They must then move their finger slowly, taking approximately 4 seconds, from the center of the nose to an angle of 45° (roughly equal to most people’s shoulder). They should do the left eye, then the right eye, then repeat. To correctly evaluate this test, they are looking for “a lack of smooth pursuit”, the nystagmus (involuntary bouncing) to begin prior to or at the 45° angle, and to be “distinct and sustained” at maximum deviation. These events are called “clues or cues” and are totaled up with three possible for each eye for a grand total of six.
  2. The Walk and Turn (WAT) is the heel to toe walking test. To administer it correctly the cop must first find a safe position for you to perform the test, instruct you to place your feet on a line, real or imaginary, in a heel to toe position with your left foot behind your right foot, and your arms by your side. He must give a demonstration of how you are to perform the test, tell you not to start until he instructs you to and ask if you understand. The cop must then tell you to take nine heel to toe steps and demonstrate, then explain and demonstrate the goofy turn they want you to perform before taking nine heel to toe steps back. He should then tell you to count the steps out loud and look at your feet while counting. He should then tell you not to raise your arms from your sides and not to stop once you begin. He should then ask again if all his instructions are understood before asking you to start. There are more clues to this test than the others, that the cop is supposed to evaluate in a standardized manner, including “stops walking”, “misses heel to toe”, “steps off-line” raising your arms more than 6 inches from your side, wrong number of steps, stepping off the line, etc. there are also clues at the “instruction stage” for starting too soon or failing to keep your balance during the instructions.
  3. The last standardized test is the One-Leg Stand (OLS). For this test, the officer must again find a safe place to instruct you, tell you to stand straight, place your feet together and hold your arms by your sides. They must then tell you that you are not to start the test until instructed and ask if you understand. Then, tell you to raise one leg, either one you choose, approximately 6 inches from the ground, keeping the foot parallel to the ground and should then demonstrate that test to you. You should further instruct you to keep both legs straight and to look at the elevated foot and count out loud in the following manner: one thousand and one, one thousand and two, etc. until told to stop. He should also give a demonstration again of this. He should then instruct you to begin the test and check his watch to determine the actual time you hold your leg up. The clues here are “sways while balancing”, “using arms to balance”, “hopping” and putting your foot down.

As you can tell, these tests are rarely given as they were meant to be administered and seldom evaluated, in a standardized, precise manner. Even the law enforcement personnel who developed them will admit that they are useless if not correctly administered and evaluated. They are also admittedly unreliable when used on people significantly overweight, with injuries or over the age of 65.

Other tests are frequently given by local police, particularly, and referred to as FSTs but are completely uncorroborated by any studies whatsoever. This includes having you touch your finger to your thumb, 1, 2, 3, 4 and 4, 3, 2, 1 or having you stand with your feet together, your eyes closed, your head back and estimate 30 seconds.

Mr. Nash is a graduate of the same course that is given to police officers at the Police Academy, sanctioned by the IOOCP and is expert at evaluating whether these tests were correctly administered and graded. Mr. Nash is also a graduate of the Drug Recognition Program given to DREs or so-called Drug Recognition Experts on the police forces and is able to appraise whether the Field Sobriety Tests in those Driving under the Influence of Drug cases were properly administered and evaluated.