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New Study Casts Doubt on Reliability of DUI Field Sobriety Tests for Marijuana (THC) and by inference Alcohol

A new double-blind, placebo-controlled randomized clinical trial with 182 participants published in the journal JAMA Psychiatry has found that field sobriety tests (FSTs) may not be accurate in identifying drivers who are under the influence of THC. The study, which was conducted by researchers at the University of California, San Diego, found that 49% of the placebo (sober) group failed DUI field sobriety tests FSTs. This means in simple terms that almost 50% of people randomly selected to perform DUI field sobriety tests will fail even when completely sober.

This study is significant because it is the first to provide strong evidence that FSTs may not be reliable in identifying drivers who are impaired by THC and other drugs including alcohol due to the high failure rate of randomized sober individuals. Double-blind, placebo-controlled randomized clinical trials with n-values or over 100 participants published in reputable journals are considered the gold standard in peer reviewed scientific research. The study’s findings could have a major impact on DUI cases in Georgia, as FSTs are often used by police and law enforcement officers to establish probable cause for a DUI arrest.

The study’s findings are also important because they raise questions about the admissibility of officer testimony regarding the results of FSTs under the Daubert standard and related laws designed to exclude “junk science.”  If the results of FSTs are not reliable, then it may be argued that officers cannot testify as to the ultimate issue of whether a driver is less safe or impaired based on the results of these field sobriety tests. The tests conducted in the study included Walk and Turn (WAT), One Leg Stand (OLS), Finger to Nose (FTN), Lack of Convergence (LOC), and Modified Romberg (ROM).

This is a complex issue, and it is likely that the courts will continue to grapple with it in the coming years. However, the study’s findings provide strong evidence that FSTs are not as reliable as once thought, and it could lead to changes in the way that FSTs are used in DUI cases.

Under Georgia law, all expert testimony must pass the Daubert gatekeeping test which is codified at OCGA 24-7-702. This includes not only scientific evidence like the Horizontal Gaze Nystagmus test but also any non-scientific expert testimony. Some trial courts are trying to limit Daubert in criminal cases to scientific evidence only and not include field sobriety tests like the walk and turn and the one leg stand. This issue was decided conclusively against those courts by the U.S.Supreme Court in Kumho Tire Co., Ltd. v. Carmichael, 119 S.Ct. 1167 (U.S. 1999).

In Kumho Tire, the U.S. Supreme Court held, the Daubert factors apply to the testimony of engineers and other experts who are not scientists. Pp. 147-153. The Supreme Court reasoned that Daubert “gatekeeping” obligation applies not only to “scientific” testimony, but to all expert testimony. Rule 702 does not distinguish between “scientific” knowledge and “technical” or “other specialized” knowledge, but makes clear that any such knowledge might become the subject of expert testimony. It is the Rule’s word “knowledge,” not the words (like “scientific”) that modify that word, that establishes a standard of evidentiary reliability. 509 U. S., at 589-590.

If you have been arrested for DUI in Georgia, it is important to speak with an experienced DUI lawyer to discuss your case. An experienced DUI lawyer can help you understand the law and your rights, and they can fight to get the best possible outcome for your case.

As an experienced DUI lawyer with over 30 years of practice, I have seen firsthand how FSTs can be unreliable. I know that FSTs can be used to unfairly target and convict innocent people. That is why I fight tirelessly to protect the rights of my clients and to get them the best possible outcome in their DUI cases.

If you have been arrested for DUI, I urge you to contact me today to schedule a consultation. I will be happy to discuss your case with you and to help you understand your options.

Contact us today to schedule a consultation.


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