Reasons Why Field Sobriety Tests are Unreliable

Field sobriety tests or FST describes a series of three tests used by law enforcement in Alabama to determine if a driver is impaired. They are also referred to as standardized tests, but there is nothing standard about them.

If you are perfectly sober, about one-third of individuals will fail a field sobriety test. If you fail, you can be arrested for DUI at the determination of the arresting officer. Field sobriety tests are objective, and there is no universal pass or fail standard. The tests are just one component of what an officer will use to make a subjective determination if you are driving under the influence.

To make matters worse, the officer may not tell you that taking a field sobriety test is optional. The standard for intoxication is 0.08% blood alcohol concentration and reaching that usually takes more than three drinks an hour for the average man, less for a woman. If you have had a drink or two with dinner and don’t feel intoxicated, do not be intimidated by the officer. You can refuse the test.

You can’t refuse a blood, breath, or urine test, required under the state’s implied consent laws, as that is a condition for operating a motor vehicle on a public highway. The driver has the statutory right to have an independent test of their blood, something the officer may not tell you.

Jason Darley is an experienced criminal defense attorney. He has spent years defending individuals charged with DUI and believes these tests can be challenged, even if they are presented as solid evidence of driving under the influence.

Three Field Sobriety Tests

Consider the approved tests used by law enforcement in the field.

They are:

  • Horizontal Gaze Nystagmus (HGN) – Refers to the eye jerking up-and-down or side-to-side when one is intoxicated. The officer shines a light a foot from your face and asks you to follow the object only with your eyes, and he is observing your ability to follow instructions and the smooth or jerky movement of the eye.

  • The Walk-and-Turn (WAT) – The driver takes nine heel-to-toe steps along a straight line, then turns on one foot and walks back the same way. Balance and ability to interpret instructions are observed.

  • The One-Leg Stand (OLS) – Hold one foot six inches off the ground and count 30 seconds. The officer is looking for balance and using your arm or foot to help you balance.

Clearly, many Americans cannot stand on one leg or walk in a straight line, whether they’ve been drinking or not. An overweight individual may have a wobbly gait that makes passing these tests impossible. An older adult or someone nervous may be shaky at the time they are pulled over. Brain injury, scoliosis, and an inner ear disorder mean you likely will fail, but the officer at the scene does not consider these standards.

Unreliable Evidence

Even law enforcement will admit that the three standard tests have problems that aid an officer in making a reasonable guess about your intoxication.

They are Subjective – An officer on the scene may administer an FST in different ways to different individuals, yielding different results. Not only does the officer’s experience and training impact the outcome, but a preexisting condition may cause you to react to the test in a way that resembles intoxication. Again, the officer does not have that knowledge. 

Lacking a Baseline – Any test requires a baseline for comparison. The officer has no idea how you would perform under normal circumstances. You may have a short leg that affects your walking or are in pain from a fall. Maybe the ground is uneven, or you have worked double shifts and are exhausted. There is simply no way to compare the results of a field sobriety test to your usual way of being before being pulled over.

Stress at Being Pulled Over – No one among us doesn’t feel pressure when encountering law enforcement. That stress may manifest as confusion, a nervous laugh, or not hearing directions. An officer may interpret stress signals as an indication you are intoxicated.

If the officer lets you drive home, that doesn’t mean you passed the test. It just means there was insufficient evidence to make an arrest.

Your Alabama Defense Attorney

If you are pulled over for suspected drunk driving, understand that police cannot require you to submit to a field sobriety test.

If you do agree, you risk providing evidence that law enforcement may use to help establish enough of a probable cause to arrest you. If you have not submitted to an FST, they will need to find other evidence to use against you.

Attorney Jason Darley is your experienced advocate, and he is available to fight your DUI charges, especially where there is not enough credible evidence to use against you. Call Mr. Darley for a free consultation at (251) 441-7772.