As an experienced DUI lawyer in Alpharetta and throughout Georgia, I've spent years challenging the so-called "science" behind field sobriety tests in court. One of the most commonly used—and misused—tools in DUI arrests is the Horizontal Gaze Nystagmus (HGN) test. Officers claim it can detect alcohol impairment with high accuracy, but a deep dive into the raw data from the National Highway Traffic Safety Administration's (NHTSA) 2007 "Robustness of the Horizontal Gaze Nystagmus Test" study tells a different story. Despite criticisms from experts and courts, this test often masquerades as reliable science, leading to wrongful arrests and convictions. Let's break it down based on the study's own data and why it's "fake science" that shouldn't hold up in your DUI case.

What is the HGN Test, and Why Does It Matter in Georgia DUI Cases?

The HGN test involves an officer moving a stimulus (like a pen or finger) side-to-side while observing your eyes for involuntary jerking (nystagmus). NHTSA claims that four or more "clues" out of six indicate a blood alcohol concentration (BAC) over 0.08—the legal limit in Georgia (O.C.G.A. § 40-6-391). Officers are trained via NHTSA manuals to tout this as 88% accurate for detecting impairment above 0.08, up from earlier claims of 77% for 0.10.

In Georgia courts, HGN results are often admitted as evidence of impairment, even though they're subjective and prone to error. But as we've seen in landmark cases like People v. McKown, 875 N.E.2d 1029 (Ill. 2007), courts require a Frye hearing to verify scientific acceptance before admitting such testimony. Similarly, in federal cases like United States v. Horn, 185 F. Supp. 2d 530 (D. Md. 2002), judges have limited HGN to mere observations, prohibiting officers from claiming scientific validity without proper foundation. Yet, despite these safeguards, HGN is still pushed as gospel in DUI stops.

The 2007 Robustness Study: NHTSA's Own Data Exposes the Flaws

NHTSA's 2007 study aimed to prove HGN's "robustness" under less-than-ideal conditions, like varying stimulus speed, height, or distance. For the first time, they released raw data, including control tests under perfect lab conditions by expert officers. The study involved 76 control administrations on subjects with BACs below 0.08.

Here's what the raw data reveals (from Tables like Table 10 in the study and color charts):

• High False Positives: In perfect conditions, 51 out of 76 subjects (67%) with BACs under 0.08 showed four or more clues—the threshold for arrest. That's two-thirds of sober people flagged as impaired!
  • Stimulus height test: 13/24 (54%) false positives.
  • Distance test: 18/26 (69%) false positives.
  • Speed test: 20/26 (77%) false positives.

These numbers come straight from the study's appendices and raw tables. NHTSA concluded HGN was "robust," but only by manipulating the criteria: They raised the clue threshold to six (not four, as taught to officers) and lowered the BAC cutoff to 0.06 (not 0.08). This "moved the goalposts" to hide the test's unreliability.

In the 2013 NHTSA manual, they mysteriously bumped accuracy from 77% (for 0.10 BAC) to 88% (for 0.08) without explanation. As critiqued in expert reviews like those by optometrists Karl Citek and Jack Richman (November 30, 2017), the study used mismatched eye assessments (camera on one eye, officer on the other), inflating errors. Even Duane's Clinical Ophthalmology notes nystagmus has over 40 non-alcohol causes, like fatigue or medical conditions.

Despite Criticisms, Why HGN Persists as "Fake Science"

Critics, including defense experts in cases like State v. Olenowski (New Jersey Supreme Court remand, 2018-2021 transcripts), argue HGN lacks peer-reviewed validation and has poor inter-rater reliability. In New Hampshire Insurance Co. v. Blue Water Offshore, LLC (S.D. Ala. 2009), the court allowed HGN admissibility under Daubert but only for the proposition the alcohol ingestion causes exaggerated nystagmus or jerking of the eye. Citek's overview in "The Horizontal Gaze Nystagmus Test" admits it's a screening tool, not proof of impairment.

Yet, HGN endures because it's quick, cheap, and courts often defer to NHTSA's self-funded studies. This is "fake science"—cherry-picked data ignoring real-world variables like officer bias, lighting, or non-alcohol nystagmus. In Georgia, where SFSTs are key to probable cause, this leads to unjust arrests.

How This Helps Your Alpharetta DUI Defense

At George C. Creal, Jr., P.C., we've used these findings to suppress HGN evidence or discredit it at trial. If you're facing a DUI in Alpharetta, remember: HGN isn't infallible. We challenge it with expert testimony, video analysis, and cross-examination, often leading to dismissals or acquittals.

Don't let flawed "science" ruin your life. Contact us today for a free consultation at (404) 333-0706 or visit www.georgecreal.com. With over 25 years fighting DUI charges in Alpharetta, Fulton County and beyond, we'll expose the weaknesses in your case and fight for your rights.

George C. Creal, Jr. is the founder of George C. Creal, Jr., P.C., Trial Lawyers, specializing in DUI defense in metro Atlanta. This post is for informational purposes and not legal advice.

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