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How many passes to each eye does the officer have to do with the light during a HGN test to be valid ?

Houston, TX |

The officer only did it 3 times. Also I read if you keep moving your head your head must be still to do the test

Attorney Answers 3

  1. Best answer

    If the officer only did three passes, then he administered the HGN test wrong. The HGN test requires a minimum of 14 passes. Two passes for equal tracking, and four passes each for lack of smooth pursuit, nystagmus at maximum deviation, and angle of onset of nystagmus prior to a 45° angle. The admission of the HGN test, is governed by a case called Emerson vs. State, 880 S.W. 2d 759 (Tex.Crim. App.1994). The Emerson case applied rule 702, which governs the admissibility of scientific evidence, to admission of the results of the HGN test. The court devised a three pronged test to determine whether the HGN test and its results are admissible in trial. The first two prongs are never really an issue, however the third prong requires the horizontal gaze nystagmus test in your case to be administered according to the tests design. Although recent case law says that slight deviations in the administration of the HGN test go to the weight to be given the test and not its admissibility, the test must neverthless be administered according to its design.You cannot simply eleminate portions of the test and still call it an HGN test with all of its "scientific" backing. The National Highway Traffic Safety Administration is an authority on the proper administration and scoring of the HGN test. They produce the manuals your officer studied to learn how to properly administer and score the HGN test. Your lawyer should have a copy of these manuals to effectively challenge this evidence, and if admitted, to effectively cross examine the officer on his/her poor performance.This answer is brief, and only scratches the surface, but I hope it helps.

    My answer is based upon the limited amount of information available at the time of writing.I am a Texas DWI Lawyer. If possible, hire an attorney who is a member of the National College of DUI Defense, who is familiar with your jurisdiction. Jim Butler-, 713-236-8744

  2. The NHTSA manual indicates six times. It also indicates that you always start with the left eye. But the failure of the officer to perform the tests exactly as the manual indicates, does not mean that the test will not be admitted in a trial. It will go to the "weight"given to the test by the judge or jury. Moving of the head means that the person being examined is not following instructions and if that causes the officer to abandon the test then he will assess all six clues against the examined person because of the failure of the ability to administer the test. All these matters are very technical in nature and a DWI/DUI attorney can examine each test and the errors in the officers administration of each test. Good Luck

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  3. Three passes for each eye, so six total. Moving your head is not a clue but it can interfere with their ability to score the test. Of course, then they can just say he was too drunk to do the test because he couldn't even keep his head still. As I've said before, DWIs are highly technical. You need an attorney who has tried hundreds of them and regulalry attends courses on ever evolving DWI law and science.

    Macy Jaggers's answer to a legal question on Avvo does not establish an attorney-client relationship. Ms. Jaggers offers everyone a free consultation to discuss their case. Feel free to call her office at 214-365-9800 to make an appointment (phones are answered 24 hours) or visit her website at for more information about her services and recent victories.

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