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Field sobriety tests are constant feature in pop culture; take this clip from Reno 911 for example:

The danger of having field sobriety tests and DUI arresting procedures regularly depicted in the movies and televisions shows we watch is that incorrect information can be perpetuated. After seeing improper field sobriety testing in your entertainment, it can be hard to know what you are and are not required to do if you are actually stopped under suspicion of a DUI. In our first edition ofDUI Talk, we aim to correct some serious misconceptions that surround one of the most common field sobriety tests- HGN.

What is the HGN Test?

You are most likely familiar with the HGN test. This is when officers ask suspects to follow a pen or other object without moving their heads using only their eyes. You may assume that this is to test if you are coherent enough to follow simple directions, or sober enough to move one part of your body without moving another; however, the purpose of this test is far more complicated (and dry) than that (stick with us through the boring part- it is important, we promise).

HGN stands for Horizontal Gaze Nystagmus. Nystagmus is the involuntary jerking of the eye which is especially apparent in people who are intoxicated. This video shows a side-by-side comparison of what the HGN Test ought to look like when completed by someone who is sober and someone who is intoxicated:

Officers will look for several key indicators while performing the HGN Test: equal tracking, smooth pursuit, and maximum deviation. Equal tracking refers to the rate in which both eyes follow the object, which must match. While looking for equal tracking, officers must also make sure that both of the suspect’s pupils are the same size; if not, police officers are instructed to provide the individual with medical assistance. Smooth pursuit refers to the “jerking” motion of the nystagmus. Eyes must appear to follow the object in a smooth route, like the above video shows. Maximum deviation is when your eyes are moved as far right or left as possible; nystagmus is most apparent prior to 45 degrees. If a police officer detects this jumping or jerking motion when the eye is moved to the very right or very left, the suspect is considered to have failed the HGN Test.

Why should you care about the HGN Test?

This is where things get interesting: in 2002, the court cited thirty-eight possible causes of nystagmus in United States v. Horn. Among these possible causes are strep throat, syphilis, vertigo, heredity, and consumption of excessive amounts of caffeine.That’s right! That same jerking motion noticeable in the eyes of an intoxicated person may also be present in the eyes of a person who drank too much coffee.

Furthermore, the HGN Test is problematic because, although police officers are trained on how to administer the test, they cannot be expected to operate like an optometrist. It would entirely unreasonable to assume that a police officer could tell the difference between nystagmus caused by intoxication, and similar involuntary eye movements caused by glaucoma or eye strain. Regardless of this fact, police officers can qualify a failed HGN Test as probable cause for a DUI arrest. Though the HGN Test is inadmissible in court in the state of Pennsylvania, it could very well be the reason that you wind up in the police station.

What should you do if asked to perform the HGN Test?

Field sobriety tests are administered for the sole purpose of finding a reason to arrest you. In this situation, the police are not on your side. They are not asking you to perform tests to exonerate you, or to prove that you are sober. They are asking you to perform tests so that they have probable cause to arrest you for a DUI.

As we will discuss in a later installment of DUI Talk, there are certain field sobriety tests that you can refuse and there are certain field sobriety tests that you must take. Because the HGN Test is inadmissible in court and so problematic, you are permitted to refuse to perform the task. Police officers WILL NOT ask for your consent to perform the HGN Test! Recognize this, and if a police officer asks you to follow a pen, etc. with your eyes, politely say, “No, thank you”.

If you or a loved one have been arrested for a DUI and are in need of representation, call us at Rehmeyer & Allatt for a free consultation: 814-343-9860