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The Three Commonly-Accepted Field Sobriety Tests

Even as little as thirty years ago, law enforcement officers were obtaining probable cause to make DUI arrests by all sorts of means that were as wildly inaccurate as they were varied. This prompted a massive study from the National Highway Traffic Safety Administration into these tests in order to find out which ones were the most accurate and how to make them better to lead to fewer mistakes, fewer false arrests, and fewer accused individuals being acquitted due to a mistake during the arrest process.

This study created three common field sobriety tests and the standards by which they should be administered: the walk-and-turn test, the one-leg stand test, and the horizontal gaze nystagmus. Today, these three tests have been improved even further and are still relied upon as the most accurate and useful tests for making arrests. However, there are still mistakes made when issuing them, and that could still lead to a false arrest.

As a driver who may be forced to take one of these tests one day, here is how each of them works as well as some of the mistakes that can lead to a false positive and wrongful arrest.

Horizontal Gaze Nystagmus Test

The horizontal gaze nystagmus test is arguably the most widely-used test due to its quick and easy nature, fairly high accuracy, and difficulty to fool. While other field sobriety tests can be fooled, a horizontal gaze nystagmus test is merely observing and looking for an involuntary muscle spasm that those who are intoxicated lack the ability to control.

In this test, the administering officer holds up a pencil, small light, or even just their finger at eye level in front of the accused individual and then asks them to follow its motion without moving their head. When the officer moves the target object slowly from side to side, they’ll watch the suspect’s eyes for any twitching. This twitching comes from an intoxicated brain losing the ability to fully control the muscles that regulate eye movement. This generally leads to a pretty high accuracy rate, making this one of the most trusted sobriety tests out there.

Walk & Turn Test

In the walk-and-turn test, the subject is asked to walk in a heel-to-toe fashion down a straight line, before turning without lifting their feet and then walking back. This test is designed to test someone’s ability to focus on a mental task as well as a physical one—generally, the officer will instruct someone on different things to do while also completing this task, such as count the number of their steps and turn after completing a particular number. Officers often look for signs that the brain is inhibited in its function by forcing it to try to handle too much at once.

Sound difficult? It is, even for many sober individuals. Walking in a heel-to-toe fashion is similar to walking on a balance beam, and that alone can test someone’s ability to walk straight. Trying to focus on this walking task while also counting your steps and then remembering to turn without lifting your feet is a tough task to handle, and many people who are perfectly sober actually fail this test. While it is a standardized test and accepted as a method for obtaining probable cause, it’s still possible for this test to yield a false positive and inaccurate results.

One Leg Stand Test

The one leg stand test is similar to the walk-and-turn in that it requires you to split your mental focus between what you’re doing and a subsequent mental task. In this test, an officer will usually instruct the test subject to stand on one foot with their other foot pointed outward. Then once they are in that position, they will ask the subject to count to 30 by thousands (“one-one thousand, two-one thousand, three one-thousand…”). Those who are intoxicated often have a lot of trouble holding their balance while also remembering how to count in this manner.

Also similar to the walk-and-turn, the one leg stand does yield a substantial number of inaccurate results as well, purely because of the difficulty of the test. Standing on one foot in the required manner isn’t easy, and for many people it takes substantial physical stamina to do so. As a result, many people can’t hold out for the entire 30 seconds. Some people forget to count by the one-thousands method. Results will vary, but in any instance, the difficulty of the test may not have been enough to allow an officer to develop any form of “reasonable suspicion” and make a lawful arrest.

For more information about your case, or if you think you may have been falsely accused of DUI, request a case evaluation by calling the Law Offices of William D. Thompson today at (570) 666-1068!