Written by attorney Steven Fisher Fairlie

PA Field sobriety tests

Standardized Field Sobriety Testing - To see this guide in it's proper format go to Standardized Field Sobriety Tests were developed as the result of research conducted in the mid 1970s for the National Highway Traffic Safety Administration ("NHTSA"). The purpose of this research was to develop standardized tests which would provide a reliable method of determining intoxication from field sobriety tests. The NHTSA has concluded that three tests, if systematically conducted according to strict guidelines, can predict whether a person may be under the influence of drugs or alcohol. The only three field sobriety tests approved by the NHTSA are the Horizontal Gaze Nystagmus "HGN" test, the Walk-and-Turn test, and the One-Leg Stand test. Police officers are theoretically trained to look for established "scoring factors" or "clues" which must be evaluated in determining whether or not intoxication exists. A finding of intoxication can only arise once a certain number of clues are identified. If less then the certain level of clues are identified, the officer should conclude that there a high degree of probability of non-intoxication. For cases that proceed to trial, it is important for defense counsel to carefully question police officers with respect to their field sobriety test training and adherence to NHTSA protocols. If a police officer is unsure of these protocols and/or the NHTSA-approved indicator system, his or her conclusions can lose credibility with a judge or jury. 1. Horizontal Gaze Nystagmus ("HGN") Test Horizontal gaze nystagmus is an involuntary jerking of the eyeball which occurs naturally as the eyes rotate in the socket. In theory, a sober person can visually follow a moving object smoothly and without the eyeball "stopping and starting". With a person is impaired by alcohol, nystagmus is exaggerated resulting in a jerking motion as the eyes rotate. In the HGN test, the officer observes a person's eyes as the eyes follow a slowly moving object such as a pen or small flashlight. 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. The NHTSA has concluded that if, between the two eyes, four or more "clues" appear, the suspect likely has a BAC of 0.10 or greater. It is important to note that even the NHTSA acknowledges that the HGN testing allows for the proper classification of only 77 percent of suspects. That is, the HGN test will result in many false positives and cannot be considered a reliable indicator of intoxication. Indeed, the HGN is not admissible in Pennsylvania courts although police are permitted to use the test to establish probable cause to arrest. People taking medication such as seizure and psychiatric medication may also "fail" the HGN test even though they are not intoxicated. 2. Walk-and-Turn Test 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 possible indicators, or "clues", of impairment. If two or more clues are identified, a person is considered to be likely intoxicated. It is important to note that even the NHTSA concedes that only 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. It is also important to note whether a person has some reason unrelated to intoxication - such as a physical disability, high-heeled shoes, use of prescribed medication, obesity, advanced age - that makes it more difficult to complete the test. It is very important to point out these issues to a judge or jury when a case goes to trial. 3. One-Leg Stand Test In the one-leg stand test, a person 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 NHTSA protocols call for the officer to observe the subject 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. Prosecutors sometimes argue that a person's "failure" of field sobriety tests such as the one-leg stand test conclusively prove a person's intoxication. However the NHTSA itself admits that only 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. And, like the walk-and-turn test, there are many factors other then intoxication that can make it difficult for a person to stand on one foot for 30 seconds. It is important to carefully examine field sobriety test evidence. In many - if not most - instances, police officers do not administer the test in full compliance with NHTSA guidelines. For example, an officer's opinion should be considered suspect if he uses improper scoring criteria, was improperly trained, incorrectly instructed the suspect on how to perform the test or did not use the standardized methodology in performing the tests. Cross-examining police officers with their own training manuals frequently exposes their lack of knowledge and skill in conducting these tests. At trial, all of these factors must be fully explored so that a judge and/or jury understand the fallibility of field sobriety testing. PBT or Preliminary Breath Testing with an Alco-Sensor device Police in Pennsylvania may use a handheld PBT device for the sole purpose of determining whether there is sufficient cause to request a more reliable chemical test. In Montgomery County, Bucks County, and the surrounding Philadelphia communities that more reliable test is usually a blood test or a breath test back at the police station.

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