DUI Testing

Standardized Field Sobriety Test

The Standardized Field Sobriety Test (SFST) is a series of three tests or exercises that are supposed to be administered and evaluated in a standardized manner. The standardized manner of testing is supposed to help take the subjectivity out of an officer's opinion that a subject either was or was not impaired. However, in practice, these exercises are not always administered or evaluated in the standardized manner. Officers in a roadside investigation often fail to follow their training for a number of reasons. Also, the underlying validity of the exercises, even if administered and evaluated according to the standardized manner has been repeatedly called into question by leading experts in this field.

The Standardized Field Sobriety Exercises were developed as a result of research sponsored by the National Highway Traffic Safety Administration (NHTSA). A formal program of training was developed and is available through NHTSA to help police officers become more skillful at detecting DUI suspects, describing the behavior of these suspects, and presenting effective testimony in court. Formal administration and accreditation of the program is provided to officers through the state.

The three tests of the Standard Field Sobriety Test are: 1. the horizontal gaze nystagmus (HGN) 2. the walk-and-turn 3. the one-leg stand.

HGN Testing

The Horizontal gaze nystagmus (or HGN) is an involuntary jerking of the eyeball 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 slow moving object such as a pen or small flashlight, horizontally with his 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 0.10 or greater. NHTSA research indicates that this test allows proper classification of approximately 77 percent of suspects. HGN may also indicate consumption of seizure medications, phencyclidine, a variety of inhalants, barbiturates and other depressants.

Divided Attention Testing

The walk-and-turn test and one-leg-stand test are "divided attention" tests. These tests require a suspect to listen to and follow instructions while performing simple physical movements. The theory behind the testing is that impaired persons typically have more 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 seven 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, uses arms to balance, loses balance while turning or takes an incorrect number of steps. NHTSA research indicates that 68 percent of individuals who exhibit two or more indicators in the performance of the test will have a BAC of 0.10 or greater.

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 a 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 65 percent of individuals who exhibit two or more such indicators in the performance of the test will have a BAC of 0.10 of greater.

The effectiveness of SFST in court testimony and evidence depends upon the cumulative total of impairment indicators provided by the three-test battery. The greater the number of indicators, the more convincing the testimony. Because SFST is administered according to national standards and is supported by significant research, it has greater credibility than mere subjective testimony.

Walk-and-Turn Test

The walk-and-turn test requires a hard, dry, level, non-slipping surface with sufficient room for the suspect to complete nine heel-to-toe steps. It should be administered under relatively safe conditions. This test loses some validity when conducted in certain weather conditions contrary to these criteria such as rain or even strong wind. The manual advises that a straight line should be clearly visible on the surface. Conditions must be such that the suspect would be in no danger if he or she were to fall. The subject and the officer's safety should be considered at all times. If these conditions do not exist, the manual advises that the suspects should be asked to perform this test elsewhere or only the HGN test should be used.

The officer also receives training in determining whether the person should be given this test at all. For example, certain people have physical problems that would make these tests more difficult to perform, i.e., people more than 65 years of age, over 50 pounds overweight, or with any physical impairments that would affect their ability to balance should not be given this test. The officer is trained to take this into account when developing their probable cause to arrest.

One-Leg Stand

The one-leg stand test must be performed on a reasonably level and smooth surface. There should be adequate lighting for the suspect to have a visual frame of reference. Conditions must be such that the suspect would be in no danger if he or she were to fall. Certain weather conditions obviously may interfere with and affect the validity of this test. This test should not be given to persons who are more than 65 years of age, more than 50 pounds overweight, or with physical impairments that interfere with balance. Persons with injuries to their legs and inner ear disorders may have difficulty with this test. Individuals wearing heels more than two inches high should be given the opportunity to remove their shoes. It is imperative that the officer observe the suspect from at least three feet away, and remain as motionless as possible while the suspect is performing this test, so as not to interfere with the test.

The one-leg-stand test also has two separate stages. The first stage is also called the Instruction Stage. The test is initiated by giving verbal instructions, followed by and accompanied by demonstration. The officer is trained to advise the suspect to stand with his or her feet together and arms down at the sides.

The officer is trained to demonstrate the initial standing position. The suspect should be told not to start the test until told to do so and acknowledge that he or she understands the instructions. The suspect should verbally acknowledge that he or she understands the instructions. There are no scoring factors involved until the suspect is into the next stage which is called the Balance and Counting Stage, unless the suspect cannot perform the test at all. In this case, the suspect would be given a maximum score of four points. This would necessitate explanation on the part of the officer. It cannot be scored simply when the suspect refuses to perform the test.

The Breath Test

After an officer has made a DUI (driving under the influence) arrest, the officer will usually request that the person take a breath test. It is important to remember that this test is voluntary in the sense that no police officer can force you to take the test. Politely refusing to take the breath test can often greatly improve your chances of avoiding a DUI conviction. When the officer asks you whether you will submit to a breath test, you are entitled to politely say "No." Refusal to take the breath test does have some negative consequences, including a driver's license suspension with a longer "hard suspension" period (or period before you are eligible for a hardship license). For example, for a first DUI arrest without any prior refusal, the administrative "hard suspension" period is 30 days if the subject takes the breath test with a result of .08 or above, while the administrative "hard suspension" period is 90 days if the subject refuses to take the breath test.

The Intoxilyzer 8000

For any breath test administered in Florida, the police will use the Intoxilyzer 8000 machine. This machine is used to measure concentration of alcohol deep within the lungs. The theory behind the test is that the concentration of alcohol within the air of the lungs has a direct correspondence with the person's blood alcohol concentration (or BAC). Various factors can affect this correspondence between alcohol in the breath and alcohol in the blood. An expert can be hired by the defense to testify about problems with the Intoxilyzer 8000 and possible alternative explanations for a result of .08 or above. For example, mouth alcohol contamination, improper use by the technician, a malfunction of the machine can all cause an inaccurate result.

Florida State Law and the Breath Test Results

If you take the breath test, and the result is a reading of .08 or higher, then Florida law provides for a presumption of impairment "per se." That means that regardless of whether your normal faculties are actually impaired by alcohol or not, the law allow for a presumption that you are impaired. If you have taken the test, it is important to speak with an attorney who is experienced in attacking breath test results. These results can often be inaccurate. It is also possible to have the breath test results suppressed or excluded from evidence for a number of reasons, including an unlawful stop, lack of probable cause for the initial stop, or because of any problem with the breath test machine that could cause an inaccurate reading. An experienced Florida DUI attorney can investigate your case, require the disclosure of all documents related to that particular machine and its repair logs, and speak with the technician who was responsible for administering your test.

Tampa Bay Florida DUI Attorneys

The attorneys at the law firm of Escobar & Associates are experienced in handling every aspect of your DUI case, from the administrative consequences with the Department of Motor Vehicles, to every facet of the criminal case. Contact our office today to schedule a free consultation with an experienced DUI attorney to discuss your case.

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