Standardized Field Sobriety Tests

The field sobriety tests given to citizens suspected of driving under the influence ( DWI ) is usually a combination of standardized field sobriety tests promulgated by the National Highway Traffic Safety Administration (NHTSA), and those inherited from other police officers. An officer becomes certified to give the standardized tests by taking a 40-hour course. Ostensibly, they graduate from the course knowing the right way to offer and grade these field sobriety tests. With regard to the Horizontal Gaze Nystagmus test (the pen test), an officer is required to practice in the field a certain number of times before being certified.

Field Sobriety Tests

Testing for Suspicion of DWI

If a police officer suspects you are driving while intoxicated, you can be pulled over and asked to take a series of tests called “field sobriety tests”. Based on these tests, you may be arrested for DWI. There are several “standard” tests that are given by police officers. These are:

  • Horizontal Gaze Nystagmus (HGN) is an involuntary jerking of the eye as one looks to the side. When an individual is impaired by alcohol this action is magnified. Officers commonly use a penlight to perform this test.
  • Walk and Turn (WAT) is a test that asks a person take nine steps in a straight line, heel to toe. After the person walks the nine steps they are asked to go back in the same manner, in the opposite direction.
  • One-Leg Stand (OLS) is a test in which an individual is asked to stand with one foot approximately 6 inches off of the ground, while counting aloud by thousands. This is done until the person is told to stop.

At Chernoff Law, we want you to know that these tests are not fool proof and leave great room for error. If you are arrested for DWI you may have to face expensive fines, possible jail time, increased insurance costs, suspension or loss of your driver’s license and a permanent criminal record. It is likely that you will need the assistance of an experienced Houston DWI lawyer to fight these charges.

Field Sobriety Tests – Flaws & Inconsistencies

The WAT and OLS tests depend on an individual’s ability to listen, carry out instructions and do various physical actions. Many people have trouble doing the required actions in a perfectly sober state. No matter how well you performed, if the police felt you didn’t follow their instructions properly, you may be arrested.

When the HGN test is done, the officer attempts to interpret whether the eyes jerked or not in an improper fashion. As opposed to the other field sobriety tests, this test is not videotaped. No one will ever see what the officer looked at when he flashed the light in your eyes. The best way to defend a DWI case is to aggressively attack the opinion that the person was intoxicated in the first place.

Standardized Field Tests

The field sobriety tests you are likely to be offered when stopped by the police on suspicion of DWI are the walk and turn, the one leg stand, and the Horizontal Gaze Nystagmus test (pen test). These are considered the “standardized” tests. On occasion, an officer will also give you the head tilt test, the finger to thumb test, the nose touch test, or ask you to recite the alphabet. Most of the time these procedures will be video-taped.

Testing on Physical and Mental Ability

What many citizens don’t know is that with regard to the one leg stand and walk and turn tests, the officer is judging them on both their physical dexterity and their mental acuity. You might be able to juggle chain saws and still “fail” the evaluation if the officer believes you didn’t sufficiently follow their instructions. The slightest variation in testing can bring you a black mark. For example, if a person stands solidly on one leg but fails to look at their pointed toe, the officer will mark them down for not following instructions.

Horizontal Gaze Nystagmus (HGN)

The Horizontal Gaze Nystagmus test, or pen test, is designed to determine whether a person’s eyes jerk involuntarily as a result of ingesting alcohol or other intoxicating substance. The officer places a stylus – usually a penlight – 15 inches from the eyes of the suspect, and waives it back and forth in front of the suspect in three repeated intervals. If the officer sees jerking they interpret its significance by determining where the jerking first occurs.

There are numerous problems with the pen test, including the fact that it’s an assessment for a medical condition that is dependent on interpretation by a person with no medical training. However, the most troubling thing about the test is that it is done in secret. Although the other tests are video-taped, which enable the jury and other witnesses in a drunk driving defense case to come to their own conclusions about how the defendant did, only the officer views the pen test. No medical expert can independently verify the officer’s interpretation.

“Standardized” Doesn’t Mean Scientific

Prosecutors attempt to portray the “standardized” DUI field tests as scientific since they are accepted by the NHTSA. In reality, there is nothing scientific about them and they achieved their status simply because they were considered the most reliable indicators of intoxication among all the tests considered. However, “reliable” is clearly relative. The NHTSA confesses that the one leg stand is only a correct indicator of intoxication 65% of the time and the walk and turn only achieves a 68% grade in making that determination. Further, even this low percentage of reliability makes the assumption that the tests were given in the proper “standardized” manner. If you have been charged with driving drunk based on field sobriety testing, contact our law office online or by phone.