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The three field sobriety tests used to gauge impairment

On Behalf of | Sep 1, 2023 | Criminal Defense

You are likely aware that driving while under the influence of alcohol is not only very dangerous, but also against the law in Texas. Police forces across the state do a great job of keeping the roads safe and are always on the lookout for impaired drivers. However, if you drink alcohol on a regular basis, you may not always know if you’ve had too much.  

If you get behind the wheel after having a few drinks and law enforcement stops you, they may administer some field sobriety tests to determine if you are an intoxicated driver. Formally known as the Standard Field Sobriety Test (SFST), this evaluation consists of three separate tests: the one-leg stand test, the horizontal gaze nystagmus (HGN) and the walk-and-turn. These tests gauge your coordination and balance, as well as your ability to focus on more than one task. Here’s what you should know about these tests. 

One-leg stand test 

The one-leg stand test is just as the name implies. The officer will ask you to stand on one foot with your other foot about six inches off the ground while counting from 1,001 (one thousand one, one thousand two, etc.) until the officer tells you to put your foot down. The officer will look for signs of unbalance such as hopping, swaying or putting your foot down. 

The horizontal gaze nystagmus (HGN) test 

When you rotate your eyes at high peripheral angles, they will involuntary jerk in what is known as horizontal gaze nystagmus. This involuntary jerking of the eyeballs happens to everyone, but if you’re intoxicated, the jerking will be more exaggerated and happen at lesser angles. When an officer administers the HGN test, they will ask you to follow an object with your eyes, such as a pen or flashlight, as they move it slowly from side to side. The officer will watch your eyes for signs of intoxication. 

The walk-and-turn test 

During the walk-and-turn test, the officer will ask you to take nine heel-to-toe steps along a straight line, then turn on one foot and return nine steps. During this test, the officer will look for signs of unbalance or incoordination, which may signal impairment. If the subject does not touch heel-to-toe, stops walking to regain balance or loses their balance while turning, they may be impaired.  

If you face charges 

Although these tests do a good job of gauging sobriety, they are not always 100% accurate. There is a chance you could be completely sober yet still fail field sobriety tests, which could result in you receiving a DUI charge. Getting handcuffed, thrown into the back of a police car and charged with drunk driving can be a traumatic experience, and the aftermath can negatively impact the quality of your life. Fortunately, if you face charges for DUI or DWI, you have the right to seek legal representation to defend against these charges.