Being pulled over on suspicion of driving under the influence (DUI) is scary and nerve-wracking. And if you’ve never been in this situation before, the only thing you probably know about these ordeals is that you’ll be asked to conduct some basic field sobriety tests. But what should you expect?
What Are Field Sobriety Tests?
Field sobriety tests are a set of three standard physical and cognitive tasks that law enforcement officers use to determine whether a driver is impaired by alcohol or drugs. These tests are often conducted on the side of the road after you’ve been pulled over. The goal of these tests is to assess your coordination, balance, and ability to follow instructions—abilities that are often impaired when a person is under the influence.
While field sobriety tests are widely used, it’s important to remember that they’re not foolproof. Even sober people can struggle with these tasks, especially under stress or in less-than-ideal conditions like bad weather or uneven ground. And then there’s the issue of technological and procedural errors.
“Police officers must follow strict rules and standards to calibrate the breathalyzer and blood tests, and there are many ways to challenge the validity of the outcome,” SBBL Law explains.
In other words, just because you’ve been asked to go through field sobriety testing doesn’t necessarily mean the results will determine your outcome. There are always options. Nonetheless, it’s helpful to understand how these various tests work.
The Horizontal Gaze Nystagmus (HGN) Test
The first test you might encounter is the Horizontal Gaze Nystagmus (HGN) test. This test focuses on the movement of your eyes. The officer will ask you to follow an object, like a pen or a small flashlight, with just your eyes while keeping your head still. As the object moves side to side, the officer will closely observe your eye movements.
Nystagmus is an involuntary jerking of the eye that becomes more pronounced when a person is under the influence of drugs or alcohol. During the test, the officer is looking for signs of this jerking, especially at maximum deviation (when your eyes are turned as far as possible to the side). If your eyes jerk noticeably or if you have difficulty following the object smoothly, the officer may interpret these signs as indicators of impairment.
However, it’s crucial to know that nystagmus can occur for reasons unrelated to alcohol consumption, such as certain medical conditions or fatigue. Therefore, while the HGN test is commonly used, it isn’t infallible.
The Walk-and-Turn Test
Another test you might be asked to perform is the Walk-and-Turn test. This test is a divided attention task, which means it requires you to concentrate on both physical and mental tasks simultaneously. The officer will instruct you to take nine heel-to-toe steps along a straight line, turn on one foot, and then return in the same manner.
During the test, the officer is watching for several specific behaviors that might indicate impairment, such as losing balance, stepping off the line, starting the test before instructions are complete, or failing to follow the heel-to-toe pattern. These behaviors suggest difficulty with coordination and following instructions, which are common indicators of impairment.
It’s important to note that even sober individuals can struggle with the Walk-and-Turn test. Factors like nervousness, unfamiliarity with the task, poor physical condition, or even the pressure of the situation can affect your performance. If you have balance issues or the ground is uneven, it can influence your ability to perform this test accurately. That’s why these tests are rarely reliable.
The One-Leg Stand Test
The final standard field sobriety test is the One-Leg Stand test. In this test, you’ll be asked to stand on one leg with the other leg raised about six inches off the ground. While maintaining this position, you’ll need to count out loud by thousands (one thousand one, one thousand two, etc.) until the officer tells you to stop, typically after 30 seconds.
Here, the officer is looking for signs that you may be struggling to maintain your balance. Swaying, using your arms for balance, hopping, or putting your foot down are also behaviors that the officer might consider indicators of impairment.
As with the other tests, factors unrelated to alcohol or drug use can affect your performance. If you have a medical condition, are tired, or simply have poor balance, you might find this test particularly challenging.
Reliability and Flaws of Field Sobriety Tests
While field sobriety tests are a standard part of DUI stops, they’re not without their flaws (as we’ve noted throughout this article). The conditions under which these tests are administered can vary widely, and many factors can affect the results, even if you haven’t had a drop of alcohol to drink.
It’s also worth noting that field sobriety tests are subjective. The officer’s interpretation of your performance plays a significant role in whether you’re deemed impaired. This subjectivity introduces a margin of error, which can sometimes lead to incorrect charges.
Stand Up for Yourself
If you’re ever in a situation where you’re asked to perform field sobriety tests, remember to stay calm and collected. Politely follow the officer’s instructions to the best of your ability, but understand that these tests are not definitive proof of impairment.
If you feel the results are inaccurate or that you were unfairly judged, you should hire an attorney to help you formulate a defense.