In this post , i continue to discuss the Metro Nashville Police Department’s DUI testing report. The first field sobriety test given is usually the horizontal gaze nystagmus test. Laboratory research by the Southern California Research Institute indicates the HGN test is 77 % accurate according to the 2006 NHTSA manual in determining blood alcohol levels over .010. There has been no peer review of these studies that I have read.
Under current Tennessee case law , the horizontal gaze nystagmus test (HGN) is inadmissible . In State of Tennessee v. Murphy , The Tennessee Supreme Court excluded the HGN test as evidence in DUI trials.