The Three Most Common Types Of Field Sobriety Tests

When it comes to DUI law, establishing “probable cause” for making an arrest used to essentially be down to an officer’s gut feeling based on tests that were about as widely varied as their accuracy levels. This led to a ton of false arrests, which prompted the need for further study and refinement of these practices. Eventually, the NHTSA developed standards for three different types of sobriety tests that could offer reasonable levels of accuracy and be conducted easily with as few mistakes as possible.

However, even though officers are supposed to be trained in how to properly issue these tests, they do still make mistakes, and officers will also still sometimes try to use tests that are not approved to try and establish probable cause and make arrests. As you might imagine, these tests are wildly inconsistent, and this inconsistency can unfortunately victimize those who may be unaware of what’s going on.

Here are the three major types of field sobriety tests as well as some factors that can influence their accuracy and may lead to a false arrest.

Horizontal Gaze Nystagmus

The horizontal gaze nystagmus test is perhaps the most widely-used test in the book because it’s extremely easy to conduct and extremely hard to fool. In this test, the suspicious officer holds up a finger, pen, or small flashlight at eye level for the person they are testing, and then moves the object back and forth to both edges of their vision. The person being tested is asked to refrain from moving their head while tracking the object with their eyes.

When someone becomes intoxicated, they lose the ability to control their muscles as well as they could before, and this often manifests itself in the muscles which control your eye movement. As a result, their eyes will often twitch and flicker back and forth. Generally, for officers this is a dead giveaway that there is some amount of intoxication present, and that they should either further investigate or make an arrest and try to obtain a blood or breath test. This is primarily because this eye motion is completely involuntary and extremely hard to avoid—many people who exhibit this symptom often don’t even know they’re doing it.

Walk & Turn

In the walk-and-turn test, the subject is often required to walk along a straight line in a heel-to-toe fashion, as though they were on a balance beam, before turning and heading back the opposite direction in the same manner. This test is designed to strain someone’s ability to perform both a mental task and a physical task simultaneously—the subject is often asked to focus on what’s ahead of them, not down at their feet, and walk an exact number of steps before turning and going back the other way for the same number of steps. This makes it particularly difficult for those who are intoxicated to be able to simultaneously keep their balance and count the appropriate number of steps.

Does this test sound difficult? That’s because it is, even while sober for many people. Walking heel-to-toe is awkward, and those who already struggle with their balance can show signs of intoxication that doesn’t actually exist, leading to false arrests and charges.

One-Leg Stand

In this test, the subject is asked to stand on one foot, with their other leg approximately six inches off the ground and toes pointed. The officer will then ask the subject to count by thousands for approximately 30 seconds. Sounds simple enough, but for many people, standing on one foot can be a challenge, especially in this pointed-toe manner.

Furthermore, this is a divided-attention test, which means that the goal is to force the subject to divide their mental capacity between two different tasks, which is often difficult for most people to do while completely sober. Counting may not seem like a difficult task, but when you combine counting with focusing on keeping your balance while standing awkwardly, it’s easy to see how you can be wrongfully arrested after failing this test.

If you have been arrested and charged with driving under the influence, speak with a Birmingham DUI lawyer now! Call Tidwell Law Group, LLC today at (205) 536-7770 for a case evaluation!