Driving under the influence is a serious offense. If you are suspected of driving under the influence, an officer may ask you to perform field sobriety tests. FSTs are used by officers to establish probable cause. The results of these tests may end up as evidence in court. South Carolina officers use three standardized FSTs: Walk and Turn, Horizontal Gaze Nystagmus, and the One Leg Stand.

Walk and Turn Test (WAT)

To test one’s balance, reaction times, and listening ability officers administer the Walk and Turn Test.

An officer will separate this test into two parts: instruction and performance. During the instruction phase of the test, an officer will ask participants to stand with their hands by their side and their feet heel to heel. The officer shows the participant how the performance part of the test should be performed.

The performance part of the test consists of taking 9 steps forward, but walking only heel-to-toe. Then, you will have to make a sharp turn and walk back the same way. During this portion of the test, the participant’s arms must be at their side, their gaze must be on their feet, and they must count their steps aloud.

If someone is intoxicated, he or she may struggle with balancing during the instruction portion of the test, performance of the test (stopping while taking steps, not walking heel to toe, not counting aloud, turning the wrong way, or using their arms to balance themselves).

Horizontal Gaze Nystagmus Test (HGN)

An officer will move a black object, normally a pen, side to side in front of your face. You are supposed to keep your gaze on that black object. Officers will check to see if your eyes are bouncing or jerking when your eyes go side to side. Nystagmus, or the involuntary jerking eye movement, is more pronounced when intoxicated.

Alcohol can make horizontal eye movement less smooth and can be a tell sign of intoxication. Those who are intoxicated do not notice their eyes jerking because it is involuntary and has no effect on one’s vision.

One Leg Stand (OLS)

Lastly, the one leg stand. During this test a participant will be asked to stand on one leg for 30 seconds. Officers will search for an even surface level to administer this test and first demonstrate what they wish the participant to do. The test consists of starting with participants’ feet together and hands by their side. When the officer commands, participants will lift one foot off the ground and count aloud to 30. Participants’ hands are supposed to stay by their side during the test and not out trying to help them balance.

During the administration of this test, officers look at a participant’s movement while they are explaining the test. Are they swaying back and forth, are they having trouble balancing while staying stagnant, etc. During the performance of the test, officers will check to see if participants are using their arms to balance, if they can’t lift their foot off the ground without hopping, are they having difficulty multitasking (counting aloud and balancing).


These tests are not 100% accurate and the administration of them can also be performed incorrectly. There are many factors and reasons why a person may fail any one of these tests. When an officer suspects you have been drinking and driving, there are many considerations: field sobriety tests, breathalyzer tests, constitutional issues, and more. Don’t panic. Know the law and your rights. If you need, hire a lawyer to help.


Learn more about what a car accident attorney can do for you, about John Henderson, and contact us for any question.

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