FIELD SOBRIETY TESTS IN TENNESSEE DUI INVESTIGATION
In order to effectively defend Tennessee DUI charges, Tennessee DUI Attorneys must be familiar with the Standardized Field Sobriety Test (SFST) developed by the National Highway Traffic Safety Administration (NHTSA). There are a number of conditions that can compromise the validity of the tests, such as leg and back injuries, obesity, and inner ear troubles. Officers throughout Tennessee are trained to use the SFST to establish probable cause for arrest in Tennessee DUI cases.
The Standardized Field Sobriety Test (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 National Highway Traffic Safety Administration (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.
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.
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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).
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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).
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CALLING THE TESTS INTO QUESTION
Many things can affect how well a Tennessee DUI suspect performs on field sobriety tests. Factors such as:
Nervousness, fatigue, injuries, intimidation, weight, age, physical condition and natural coordination, the distraction of traffic and lights, weather conditions, and the clarity of the DUI officer's instructions and demonstration can compromise the validity of the tests.
Additionally, it is not uncommon for a Knoxville DUI, Gatlinburg DUI, or Pigeon Forge DUI to occur in a place where there is no flat location to perform the field sobriety tests. Any tests that are conducted on a surface other than a flat, dry surface produce questionable results.
Contact us for a free DUI consultation.
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Implied Consent
In Tennessee, anyone who drives an automobile or other motorized vehicle is deemed to have given consent to have a chemical test performed on their blood, breath, or urine. The purpose of the "implied consent" to a chemical test is for law enforcement to determine the presence and level of alcohol or drugs in Tennessee DUI cases. Before an officer may take a blood or breath sample for testing, the officer must have reasonable grounds to believe that a person was driving under the influence of alcohol, drugs, or any other intoxicant. The results of the blood or breath tests are admissible in Tennessee DUI cases as evidence in court only if the test was performed within two hours following such person's arrest or initial detention by the officer and the test was conducted properly.
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Implied Consent Penalties
In Tennessee, if a court finds that a driver has violated the implied consent law, the judge will revoke such driver's license for a period of one to five years depending upon the specific circumstances of the case. If a driver violates the implied consent law while driving with a driver license that is revoked, suspended, or cancelled for DUI, vehicular assault, vehicular homicide, or aggravated vehicular homicide, the violation is a Class A misdemeanor punishable with a minimum mandatory sentence of five (5) days to a maximum of eleven months and twenty-nine days in jail and a fine up to one thousand dollars ($1,000.00).
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Chemical Tests
In Tennessee DUI cases, a law enforcement officer may request a person suspected of committing the offense of DUI to submit to a chemical test. The officer may request a blood test, a breath test, or both in order to determine the level of alcohol or presence of drugs or other intoxicants in a person's blood. Before an officer may take a blood or breath sample for testing, the officer must have reasonable grounds to believe that a person was driving under the influence of alcohol, drugs, or any other intoxicant. The results of the blood or breath tests are admissible in Tennessee DUI cases as evidence in court only if the test was performed within two hours following such person's arrest or initial detention by the officer and the test was conducted properly.
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Blood Tests
In Tennessee DUI cases, a law enforcement officer may request a person suspected of committing the offense of DUI to submit to a blood test to determine the level of alcohol or presence of drugs or other intoxicants of that person's blood. However, before an officer may take a blood or breath sample for testing, that officer must have reasonable grounds to believe that the person to be tested was driving under the influence of alcohol, drugs, or any other intoxicant.
The results of the blood test are admissible in Tennessee DUI cases as evidence in court only if the test was performed within two hours following such person's arrest or initial detention by the officer, the test was conducted properly by a licensed medical professional, and the blood sample was properly preserved and submitted to the Tennessee Bureau of Investigation for forensic testing.
If a proper blood test is administered, and the result of the test is .08% or higher, there is a presumption that the person's ability to drive was sufficiently impaired to constitute a DUI in Tennessee.
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Breath Tests
In Tennessee DUI cases, a law enforcement officer may request a person suspected of committing the offense of DUI to submit to a breath test to determine the level of alcohol or presence of drugs or other intoxicants of that person's blood. However, before an officer may take a breath sample for testing, that officer must have reasonable grounds to believe that the person to be tested was driving under the influence of alcohol, drugs, or any other intoxicant.
The results of the breath test are admissible in Tennessee DUI cases as evidence in court only if the testing officer is able to testify that the tests were performed in accordance with the standards and operating procedures of the forensic services division of the Tennessee Bureau of Investigation and that he was properly certified in accordance with those standards. The officer must also be able to testify that the evidentiary breath testing instrument used was certified by the forensic services division, was tested regularly for accuracy and was working properly when the breath test was performed. The officer must further be able to testify that he/she observed the driver for twenty minutes prior to giving the test, and that during this period, the driver did not have foreign matter in his/her mouth, did not consume any alcoholic beverage, smoke, or vomit. The officer must further provide evidence that he/she followed the prescribed operational procedure and must identify the printout record offered in evidence as the result of the test given to the person tested.
If a proper breath test is administered, and the result of the test is .08% or higher, there is a presumption that the person's ability to drive was sufficiently impaired to constitute a DUI in Tennessee.
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