HGN Tests (Pen Light)
Broward County DUI defense attorneys routinely see DUI investigators conducting the pen light exercise when conducting an investigation. The proper name for this test is Horizontal Gaze Nystagmus and it is designed to detect impairment based on a jerking of the eye at certain angles. HGN exercises are unique in that of all standard field sobriety exercises, HGN is a medical test requiring certain training an experience before being admissible in a defendants Broward County DUI trial.
Broward County DUI Attorney William Moore Criminal Defense explains that a 1981 study concluded that the Gaze Nystagmus could correctly identify participants at or above a BAC of 0.10 seventy-seven percent (77%) of the time, that the walk and turn test could correctly identify participants as being at or above a BAC of 0.10 sixty-eight percent (68%) of the time and the one leg stand test could correctly identify participants at or above a BAC of 0.10 sixty-five percent (65%) of the time. Further, the study stated that when the results of the Gaze Nystagmus with the walk and turn test were combined, they could accurately identify a person at or above a BAC of 0.10 level eighty percent (80%) of the time. Not to be forgotten, the authors also noted a 32% false arrest rate in the overall statistics.
Another NHTSA commissioned study was conducted in 1983. This study was to standardize practical and effective procedures for police officers to use in reaching a decision regarding the arrest of a possible DUI driver. The results of this study echoed the statistical results of the laboratory testing summarized in 1981 by Tharp, Burns and Moskowitz in Development and Field Tests for DUI Arrests.
NHTSA funded yet another study to validate the SFSTs. A study
conducted in Colorado in 1995 was commissioned to examine the results of arrests from seven Colorado law enforcement agencies. A Colorado Validation Study of the Standardized Field Sobriety Test (SFST) Battery (1995) In this study officers were old to identify drivers who had a BAC over 0.05% (between 0.05%).099%) and also drivers who had a BAC over 0.10%. The study found that officers were 86% correct in their determination to arrest or release a motorist.
For more information on HGN, contact our Broward County office today.