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DUI Field Sobriety Testing

Field Sobriety Testing

Patrick Ferris is a Georgia DUI lawyer serving Coffee County and located in Douglas, GA. If you are pulled over for a potential DUI charge, know your rights. The field sobriety tests administered at roadside are not objective and measureable. They are subjective physical agility exercises that are optional. You are within your rights to politely decline these tests.

When a driver is arrested on suspicion of DUI in Georgia, he or she may be asked to perform one or more of the following field sobriety tests: the Horizontal Gaze Nystagmus ("nystagmus" refers to eye motion), the one-leg stand, and the walk-and-turn. These tests are largely subjective. Even when administered correctly, they are frequently inaccurate. Circumstances such as weather, roadside conditions, driver's weight, pre-existing injury, illness, attire, etc. can affect the outcome of such field sobriety tests. Unfortunately, although it's common knowledge that these tests are not the best indicators of intoxication, results are still allowed in the courtroom.

Standardized Field Sobriety Tests

From National Highway and Traffic Safety Administration (NHTSA) Standardized Field Sobriety Test (SFST) Training Management System:

The SFST is a battery of three tests administered and evaluated in a standardized manner to obtain validated indicators of impairment and establish probable cause for arrest. These tests were developed as a result of research sponsored by the NHTSA and conducted by the Southern California Research Institute. A formal program of training was developed and is available through NHTSA to help law enforcement officers become more skillful at detecting DWI suspects, describing the behavior of these suspects, and presenting effective testimony in court. Formal administration and accreditation of the program is provided through the International Association of Chiefs of Police (IACP). The three tests of the SFST are:

  • Horizontal Gaze Nystagmus (HGN),
  • Walk-and-Turn (WAT),
  • and One-Leg Stand (OLS).

These tests are administered systematically and are evaluated according to measured responses of the suspect.

Horizontal Gaze Nystagmus (HGN) Testing

Horizontal Gaze Nystagmus is an involuntary jerking of the eye that occurs naturally as the eyes gaze to the side. Under normal circumstances, nystagmus occurs when the eyes are rotated at high peripheral angles. However, when a person is impaired by alcohol, nystagmus is exaggerated and may occur at lesser angles. An alcohol-impaired person will also often have difficulty smoothly tracking a moving object. In the HGN test, the officer observes the eyes of a suspect as the suspect follows a slowly moving object such as a pen or small flashlight, horizontally with his or her eyes. The examiner looks for three indicators of impairment in each eye: if the eye cannot follow a moving object smoothly, if jerking is distinct when the eye is at maximum deviation, and if the angle of onset of jerking is within 45 degrees of center. If, between the two eyes, four or more clues appear, the suspect likely has a BAC of 0.08 or greater. NHTSA research found that this test allows proper classification of approximately 88 percent of suspects (Stuster and Burns, 1998). HGN may also indicate consumption of seizure medications, phencyclidine, a variety of inhalants, barbiturates, and other depressants.

Walk and Turn

The Walk-and-Turn test and One-Leg Stand test are "divided attention" tests that are easily performed by most unimpaired people. They require a suspect to listen to and follow instructions while performing simple physical movements. Impaired persons have difficulty with tasks requiring their attention to be divided between simple mental and physical exercises.

In the Walk-and-Turn test, the subject is directed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. The examiner looks for eight indicators of impairment: if the suspect cannot keep balance while listening to the instructions, begins before the instructions are finished, stops while walking to regain balance, does not touch heel-to-toe, steps off the line, uses arms to balance, makes an improper turn, or takes an incorrect number of steps. NHTSA research indicates that 79 percent of individuals who exhibit two or more indicators in the performance of the test will have a BAC of 0.08 or greater (Stuster and Burns, 1998).

One Leg Stand

In the One-Leg Stand test, the suspect is instructed to stand with one foot approximately six inches off the ground and count aloud by thousands (One thousand-one, one thousand-two, etc.) until told to put the foot down. The officer times the subject for 30 seconds. The officer looks for four indicators of impairment, including swaying while balancing, using arms to balance, hopping to maintain balance, and putting the foot down. NHTSA research indicates that 83 percent of individuals who exhibit two or more such indicators in the performance of the test will have a BAC of 0.08 of greater (Stuster and Burns, 1998).

Combined Measures

When the component tests of the SFST battery are combined, officers are accurate in 91 percent of cases, overall, and in 94 percent of cases if explanations for some of the false positives are accepted (Stuster and Burns, 1998). The original NHTSA research found different accuracies for the SFST Battery than reported in the more recent study. Tharp, Burns, and Moskowitz (1981) reported accuracies of 77 percent for the HGN, 68 percent for the Walk and Turn, and 65 percent for the One Leg Stand components; 81 percent of officers' arrest decisions at 0.10 BAC were correct when all three measures were combined. In contrast, Stuster and Burns (1998) found greater accuracies in making arrest decisions on the basis of SFST results in their study at 0.08 percent BAC, as described previously and summarized in the following table.

Field Sobriety Testing Administration

Other field sobriety tests include finger tapping, hand clapping, counting backwards, or reciting the alphabet. These activities are designed to check "divided attention", a critical skill in operating a motor vehicle. Another notorious field sobriety test is the Preliminary Alcohol Screening (PAS) test. This is a portable breath test to determine the presence of alcohol. The officer is supposed to advise the suspect that the test is voluntary. However, they often fail to follow procedure. There are many people who cannot perform these tests to the officer's satisfaction due to a non-incriminating reason. Unfortunately, these drivers are often stuck with a DUI charge. The most important thing to know about the Field Sobriety Tests is that a skilled defense lawyer will know how to handle them in court. Call Patrick Ferris today at (912) 384-1099 for your best chance at beating the charges.

Sobriety Checkpoints

The purpose of a sobriety checkpoint or roadblock is to allow law enforcement to view drivers for indications that they may be driving while under the influence of drugs or alcohol. This can be done on virtually any public road including highways and freeways but there must be probable cause to place the roadblock at the location. Also, although Georgia DUI laws and the U.S. Supreme Court provide for the legality of such roadblocks, law enforcement must still have a probable cause before arresting you on DUI charges. If you are stopped at one of these sobriety checkpoints, you will be asked to produce your license and registration. Inquiries will also be made as to whether you have been drinking or not.

Roadblocks in Coffee County, GA

Even if you underwent a breath or blood test, field sobriety tests, made incriminating statements, or provided other incriminating evidence, a roadblock can produce grounds to fight your DUI charge. There are established guidelines that must be followed in order for your stop and any subsequent arrest to be valid. Patrick Ferris is an experienced Coffee County DUI lawyer in Douglas, GA who understands what to do when a charge is based on a roadblock stop. Call Patrick Ferris today at (912) 384-1099 for your best chance at beating the charges.