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The Role of Field Sobriety Tests in Lexington County DUI Arrests

When someone is pulled over for suspected driving under the influence (DUI) in Lexington County, South Carolina, field sobriety tests (FSTs) often play a crucial role in the ensuing investigation. Understanding these tests, how they are administered, and their legal implications can be vital for anyone facing DUI charges.

What are Field Sobriety Tests?

Field sobriety tests are a series of physical and cognitive exercises that law enforcement officers use to assess a suspect’s level of impairment. In South Carolina, the most commonly used FSTs include the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn test, and the One-Leg Stand test. These are standardized by the National Highway Traffic Safety Administration (NHTSA), but their administration and interpretation can vary.

  1. Horizontal Gaze Nystagmus (HGN) Test: This involves an officer observing the eyes of a driver as they slowly move a pen or similar object from side to side. The officer looks for signs of nystagmus, an involuntary jerking of the eyeball, which can become exaggerated due to impairment from alcohol.
  2. Walk-and-Turn Test: This test requires the suspect to walk nine steps, heel-to-toe, along a straight line, then turn on one foot and return in the same manner. This test assesses the ability to perform tasks requiring attention, balance, and coordination.
  3. One-Leg Stand Test: The individual must stand with one foot approximately six inches off the ground and count aloud by thousands until told to put the foot down. This test measures balance, coordination, and the ability to follow instructions.

Reliability and Controversy

While field sobriety tests are a standard tool in DUI detections, their reliability can be contentious. Research suggests that even under ideal conditions, the accuracy of FSTs in predicting a blood alcohol concentration (BAC) of 0.08% or higher is not infallible. According to a study sponsored by the NHTSA, the accuracy of the combined three tests when administered correctly was found to be 82% [source: NHTSA].

Critics argue that factors such as age, weight, medical conditions, and even footwear can affect an individual’s performance on these tests. Furthermore, the subjective nature of what an officer considers as “failing” an FST adds another layer of controversy.

Legal Considerations in South Carolina

In South Carolina, as in other states, participation in field sobriety tests is voluntary. Motorists have the right to refuse these tests without direct legal penalties, such as fines or jail time. However, refusal can be used as evidence in court and might influence the outcome of a DUI case.

Additionally, it’s essential to know that if arrested for a DUI in Lexington County, the implied consent law requires you to submit to chemical tests (like breath, blood, or urine tests) to determine your BAC. Refusal to undergo these tests can result in immediate administrative penalties, including driver’s license suspension.

Defending Against DUI Charges in Lexington County

For those accused of DUI based on the results of field sobriety tests, there are several defense strategies that can be employed. An attorney can challenge the administration of the tests, the conditions under which they were performed, or the qualifications of the officer conducting the tests. Moreover, evidence such as medical records or witness testimonies can be used to explain poor performance on sobriety tests that may not be related to alcohol consumption.


Field sobriety tests play a significant role in DUI arrests in Lexington County, but their results are not definitive proof of impairment. If you face DUI charges, it’s crucial to seek guidance from an experienced legal professional who understands the nuances of DUI law and the science behind sobriety testing. By carefully examining the circumstances of your arrest and the methods used to administer these tests, they can provide a robust defense on your behalf.

For further reading and a deeper understanding of your rights and possible defenses in DUI cases, consulting with a knowledgeable attorney like those at Thompson & Hiller Defense Firm can be an invaluable step