How Do Field Sobriety Tests Work?

Field sobriety tests are a set of physical and cognitive assessments that law enforcement officers use to determine whether a driver may be impaired by alcohol or other substances. These tests are often performed at the scene when a driver is suspected of Driving Under the Influence (DUI). Below are answers to common questions about how these tests work.
What Are the Standard Field Sobriety Tests?
These tests are standardized by the National Highway Traffic Safety Administration (NHTSA):
- The Horizontal Gaze Nystagmus test measures involuntary jerking of the eyes, which can become more pronounced when a person is intoxicated. The officer instructs the driver to follow a moving object, such as a pen or flashlight, with their eyes.
- The Walk-and-Turn test assesses balance, coordination, and the ability to follow instructions. The driver is asked to take a specified number of steps, heel-to-toe, in a straight line, turn around, and return in the same manner.
- The One-Leg Stand test requires the driver to raise one leg off the ground, hold it for a certain period, and count out loud. This test evaluates balance and concentration, both of which can be affected by intoxication.
In certain situations, officers may use non-standardized tests or alternative methods to assess impairment. These are less common and are generally not as widely accepted as the standardized tests approved by the NHTSA. Examples include asking drivers to recite the alphabet or count backward.
How Accurate Are Field Sobriety Tests?
The NHTSA established the standardized tests to improve accuracy, but they are not infallible. Studies show that the ‘Horizontal Gaze Nystagmus test’ is considered the most reliable, with an accuracy rate of around 77% in identifying drivers with a Blood Alcohol Content (BAC) above the legal limit. The ‘Walk-and-Turn test’ is estimated to be around 68% accurate, while the ‘One-Leg Stand test’ has an accuracy of approximately 65%.
Environmental conditions, such as poor lighting or an uneven surface, may affect a driver’s performance on the tests. Physical limitations, age, or medical conditions unrelated to intoxication can also interfere with a driver’s ability to complete the tasks as instructed. Therefore, while field sobriety tests are often used as part of the process to assess impairment, they are not absolute indicators and can be challenged in legal proceedings.
Can Drivers Refuse to Take Field Sobriety Tests?
In Georgia, drivers are not legally required to take field sobriety tests. Refusing these tests, however, may still lead to arrest if the officer believes there is probable cause. It is important to understand that while field sobriety tests can contribute to an officer’s decision to request further testing or make an arrest, they are not definitive proof of impairment and can be challenged in court if necessary.
What Happens if a Driver Fails the Field Sobriety Tests?
Georgia’s current legal limits for Blood Alcohol Concentration (BAC) are:
- Drivers under 21: 0.02%
- Drivers over 21: 0.08%
- Commercial drivers: 0.04%
Failing a field sobriety test may lead to further investigation, including possible arrest and a request for further testing. If those reveal a blood alcohol content over the legal limit, that evidence may be used in court. However, these results can also be challenged in legal proceedings. A criminal defense lawyer might question whether the officer correctly administered the tests, if environmental factors affected performance, or if other factors impacted the results.
How Can a Lawyer Help After a Field Sobriety Test?
If you or a loved one was arrested after a field sobriety test, consulting a lawyer may be beneficial. They can examine the circumstances of the arrest, analyze the administration of the tests, and assess the overall legality of the stop. Our Savannah criminal defense lawyers work to identify any potential defenses, such as procedural errors, factors affecting test accuracy, or issues with the validity of the probable cause used by the officer.
The Savannah Criminal Defense Lawyers at Kicklighter Law Represent Clients Facing Charges Related to Field Sobriety Tests and DUI
Reach out to the trusted Savannah criminal defense lawyers at Kicklighter Law to learn how we might assist with your defense. To schedule an initial consultation, call our Springfield, Georgia, office at 912-754-6003 or contact us online. We gladly serve clients in Effingham County, Savannah, and the surrounding areas.