Got a DUI Based Solely on Horizontal Gaze Test

[falseaccusationvictim]

Your "genetic nystagmus" should appear different than HGN/VGN brought on by alcohol or drug impairment. It is a very telling test and one that cannot be masked by the actions of the subject. The HGN can be the single most accurate and objective of all the tests. Being honest in responses to the officer's questions and performing the additional tests in addition to the HGN would help to affirm any genetic predisposition. So, since most the general public has no such genetic predisposition, it will remain an effective part of the evaluation process when utilized properly by appropriately trained officers. The legal standard is not that the observed physiological response might have some other explanation, but whether the observed response is consistent with impairment and whether the totality of the circumstances (and observations) give rise to articulable probable cause to believe that the subject is too impaired to safely operate a motor vehicle. That standard is a good deal less than absolute certainty.

Also, the HGN/VGN is designed to be used as part of a battery of tests, and not as the SOLE test. In fact, NONE of the individual tests comprising the SFSTs are designed to be valid on their own as their individual reliability can vary between 70% and 88% (depending on the study), and taken as a battery can be effective in 91% to 94% of cases.

I'm sure the tests are accurate in cases where the subject has no health problems and the officer has the right experience, the problem is this isn't always the case and people get falsely accused by dumb police officers.

[cdwjava]

I'm sure the tests are accurate in cases where the subject has no health problems and the officer has the right experience, the problem is this isn't always the case and people get falsely accused by dumb police officers.

As I mentioned, the SFSTs are designed to be used as a battery and when taken together can be an accurate tool in the evaluation of impairment. The standard necessary for an arrest is NOT absolute certainty or even so high as to overcome reasonable doubt. The burden of proof necessary for the arrest (and the resulting chemical test) is only "probable cause." The defense is welcome to challenge the evaluation all they want, though this is often a fruitless and expensive task for the defense it can be done.