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Drug Recognition Experts (DREs) are law enforcement officers trained to identify people operating vehicles under the influence of drugs and substances other than alcohol. Different jurisdictions take a variety of approaches to DRE testimony. Some jurisdictions hold DRE protocol and evidence to be scientific evidence; some do not. Some jurisdictions permit DRE testimony to be introduced as expert testimony (usually under Rule of Evidence 702 or the equivalent in that state), while some jurisdiction require DRE testimony to be introduced as non-expert opinion testimony. Some jurisdictions analyze DRE testimony through the lens of Daubert, while other jurisdictions use the Frye analysis. The following is a chart which lists appellate (unless otherwise noted) cases that address the admissibility of DRE protocol and/or DRE testimony in court and discuss DRE testimony through the evidentiary lens of either Frye or Daubert. Under the chart, there are case summaries for each of these cases and additional case summaries in which courts admitted or accepted the DRE protocol and testimony into evidence. For a well-developed state-specific look into treatment of DRE evidence and testimony, Oregon has an expansive and easily accessible set of cases on the topic.



U.S. v. Everett, 972 F. Supp. 1313 (D. Nev. 1997). In this case, the U.S. District Court held that: (1) the factors for determining whether expert scientific testimony is admissible under Daubert include whether the theory or technique employed by the expert is generally accepted in the scientific community, whether it has been subjected to peer review and publication, whether it has been tested, and whether the known or potential rate of error is acceptable, and (2) upon an appropriate foundation being laid, the DRE protocol conducted by the witness, together with his conclusions drawn therefrom, would be admissible to the extent that the witness can testify to the probabilities, based upon his or her observations and clinical findings, but could not testify, by way of scientific opinion, that the conclusion was an established fact by any reasonable scientific standard.



Williams v. State, 710 So.2d 24 (D. Ct. App. Fla. 1998). In this case, the Florida District Court of Appeals held that the DRE Protocol in general was not scientific. However, the court also held the HGN, VGN and LOC aspects of the test are scientific in nature but do not need to be analyzed under Frye because they are not new or novel.

"The defendant contends that the trial court erred in admitting the DRE testimony and evidence because the State failed to establish the reliability of the DRE protocol at the hearing. According to the defendant, the DRE protocol constitutes a scientific test, and fails to meet the Frye standard as generally accepted by the relevant scientific community. We disagree and affirm the trial court's order granting the State's motion to admit the DRE testimony and evidence, including the standardized field sobriety and horizontal gaze nystagmus tests. In order to accurately address the issues as framed by the trial court, we must first distinguish between the general portion of the DRE protocol and its subsets, the HGN, VGN, and LOC."



People v. Ciborowski, 55 N.E.3d 259 (App. Ct. Ill. 2016). In this case, the Appellate Court of Illinois affirmed the field of “drug recognition” as an area of expertise. The court held that the trial court in this case did not abuse its discretion in allowing limited testimony from a DRE into evidence.



State of Maryland v. Consolidated Cases, 2012 Md. Cir. Ct. (unpublished). In these cases, the court considered the admissibility of drug recognition expert (DRE) testimony in the state of Maryland. The court heard conflicting expert testimony on the reliability of DRE testing. One of the defense experts testified that the nystagmus tests performed as part of the DRE’s battery of tests was being performed inadequately and that DREs lacked the medical background to properly determine the cause and implications of nystagmus. Another defense expert testified that the variable nature of the test (like being able to pick and choose only the “important” elements of the test) severely undermined its scientific credibility and that some of the medical information in the DRE handbook was blatantly incorrect. The court used the Frye standard to determine the eligibility of DRE testimony in court. The court considered that previous courts had ruled that DRE testimony was admissible but not as expert scientific testimony and also considered that under the Daubert standard, the present scientific testimony would suggest that DRE testing was not generally accepted in a properly-defined scientific community. The court cited additional testimony saying that many of the factors used in DRE analysis are not used in the medical community to determine drug use. The court ultimately concluded that DREs were not qualified to testify on the impairment of suspects and that DRE testimony was more prejudicial than beneficial, so it granted the defendants’ motion to exclude the testimony of the DREs.



Commonwealth v. Remy, 40 N.E.3d 1056 (2015) (unpublished). In this case, the Appeals Court of Massachusetts upheld case law stating that an opinion regarding a defendant’s sobriety is a lay opinion, and not an expert opinion (citing Commonwealth v. Brown, 83 Mass. App. Ct. 772 (2009) that the evidence is not scientific). An officer may testify to a defendant’s apparent intoxication without laying any foundation for expertise because, unlike opinions based on scientific methods, the foundation for testimony regarding sobriety falls within the common experience and knowledge of jurors. However, the Appeals Court upheld the officer’s qualification as a DRE (specifically his training and experience in administering field sobriety tests) because it was highly relevant to the jury’s assessment of his testimony about the defendant’s performance on field sobriety tests.



State v. Klawitter, 518 N.W.2d 577 (Minn. 1994). In this case, the Supreme Court of Minnesota held that the DRE Protocol was not a new or novel scientific test under Frye, but allowed the officer’s testimony in the case to be entered into evidence as non-expert testimony.

"We are of the opinion, however, that the protocol in question does not demand the kind of scrutiny required for the presentation of some novel scientific discovery or technique. The real issue is not the admissibility of the evidence but the weight it should receive, and that is a matter for the jury to decide without being led to believe that the evidence is entitled to greater weight than it deserves. Therefore, in the courtroom the officer shall not be called a 'Drug Recognition Expert.' Perhaps the officer can be called a 'Drug Recognition Officer' or some other designation which recognizes that the officer has received special training and is possessed of some experience in recognizing the presence of drugs without suggesting unwarranted scientific expertise."

State v. Scheffler, 2014 WL 4957113 (unpublished). In this case, the Minnesota Court of Appeals held that while opinion testimony by a DRE that a person is impaired may not be sufficient, without more, to support a guilty verdict under Klawitter, the DRE’s testimony in this particular case was not the only evidence and the evidence was more than sufficient to sustain the conviction.

State v. Cammack, 1997 Minn App. LEXIS 278 (unpublished). This case supports the use of DRE protocol and testimony. In it, the defendant argued that the DRE interview should have been videotaped and that the court should have given the jury some cautionary instruction about DRE testimony. The appellate court disagreed.



State v. Pulliam, 378 Mont. 537 (2015) (unpublished). In this case, the Supreme Court of Montana held that the DRE trooper’s qualifications as an expert were established under Montana Rules of Evidence, as the trooper had been with the highway patrol for over 12 years and had seen over 40 cases involving methamphetamine in the past year; he had participated in several weeks of criminal interdiction training each year; and he testified about the selection process for Drug Recognition Expert (DRE) training, its prerequisites, the training course itself, and the DRE evaluation process. 



State v. Daly, 775 N.W.2d 47 (Neb. 2009). In this case, the Nebraska Supreme Court held that DRE protocol was a sufficiently valid methodology under Daubert to support a DRE’s testimony at trial on a DUI charge that, based on his observations, a suspect was under the influence of drugs. The court explained that a DRE examination involves, among other things, the ruling in or out of medical conditions that could be responsible for the suspect’s impairment.


New Jersey

State v. Michael Olenowski (2020). New Jersey Justices are currently reviewing State v. Michael Olenowski .  The central question before the Supreme Court is whether evidence obtained by Drug Recognition Experts (DREs)– which, in this case, included testimony that the defendant Olenowski was under the influence of narcotics while driving – is admissible under the standard articulated in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). A special master is reviewing the science behind it. The court’s decision in State v. Michael Olenowski is likely to become increasingly relevant as the state seeks to legalize recreational marijuana use.


New Mexico

State v. Aleman, 194 P.3d 110 (N.M. Ct. App. 2008). In this case, the New Mexico Court of Appeals held that the DRE Protocol is not a scientific test but would meet the Daubert standard anyway.

"We determine that the Protocol is not scientific in its entirety, but that the State laid an adequate foundation to introduce the individual, scientific steps of the Protocol. Although we conclude that the Protocol as a whole is not scientific, even if we were to hold otherwise, we would affirm because the State established a sufficient scientific foundation for the Protocol under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993) and State v. Alberico, 116 N.M. 156, 861 P.2d 192 (1993). Because the State has established the scientific reliability of the Protocol, we further determine that a DRE may testify as an expert witness regarding the administration and results of the Protocol as it is applied to a particular defendant. Last, we hold that minor variations in the administration of the Protocol do not necessarily undermine the admissibility of Protocol evidence. We therefore affirm the decisions of the district court as to both Defendants, which denied Defendants' motions to exclude the testimony of the DREs."


State v. Gonzales, 2017 WL 747874 (unpublished). In this case, the Supreme Court of New Mexico upheld a conviction based partly off of erroneously admitted DRE evidence. In the defendant's trial, the state did not lay an adequate foundation for the introduction of DRE evidence, but the trial court admitted the evidence anyway. On appeal, the state conceded that the trial had erred in admitting the evidence, but argued that it was harmless error. The New Mexico Court of Appeals agreed and reversed the defendant's conviction. However, upon the state's writ of certiorari, the New Mexico Supreme Court considered the entirety of the officer's testimony and used it to hold that the introduction of the testimony was harmless error and therefore uphold the defendant's conviction. In its opinion, the court court stated that a full DRE analysis is helpful, but not required in every case, and denied to overturn the conviction based on the fact that the arresting officer did not complete a full DRE analysis.


New York

People v. Quinn, 580 N.Y.S.2d 818 (1991). In this case, the District Court for Suffolk County undertook an extensive analysis and determined that DRE Protocol is a scientific test, and it used the Frye test to find that the evidence was admissible. The defendant's conviction was later overturned, but on different procedural grounds unrelated to the court's DRE testimony analysis.

"The court holds that the People have successfully established that both the HGN test and the DRE protocol meet the standards enunciated by Frye (supra) and Middleton (supra). In coming to this conclusion, the court has considered the credible and unrefuted testimony of nine witnesses each of whom stated that both HGN and the protocol permit the DRE to reliably and accurately determine whether an individual is impaired, and if so, by what classification of drug. Further, the court found the People's evidence to be persuasive. The protocol is relatively simple. Jurors should have no trouble understanding the testimony of the DRE witness. This is not a case of a procedure so complicated and so technical that a :lay jury [might] rely to an even greater degree on the expert witness...[whose] testimony may be accepted and credited without being properly evaluated.'"



State v. Sampson, 6 P.3d 543 (Ct. App. Ore. 2000) In this case, the Court of Appeals of Oregon held that DRE Protocol was a scientific test, and the court used a modified Daubert test to find that the evidence was admissible. 


"Our consideration of the various factors that weigh for and against admission of scientific evidence leads us to conclude that the underlying proposition of the DRE protocol--that ingestion of controlled substances causes a variety of symptoms detectable by a trained officer--is sufficiently reliable to justify admission of the protocol's results into evidence. Here, the state is offering the protocol as evidence tending circumstantially to make more probable a fact of consequence--that defendant was under the influence of a controlled substance. For that limited purpose, the DRE protocol is relevant under OEC 401. Furthermore, it meets the helpfulness requirement of OEC 702 by informing jurors of the significance of the results of FSTs and the other components that make up the protocol."


But see Oregon v. Aman, 95 P.3d 244 (Ct. App. Ore. 2004). In this case, the Court of Appeals refined its holding in Sampson and held that in a prosecution for driving under the influence of controlled substances, the trial court erred in admitting evidence of the 12-step Drug Recognition Expert (DRE) procedures and results as scientific evidence to prove defendant had been under the influence of a controlled substance, in the absence of the corroborating toxicology urinalysis report, which deprived the test of a major element of its scientific basis, rendering the test inadmissible as scientific evidence.


State v. Beltan-Chavez, 286 Or.App. 590 (2017). In this case, the Oregon Court of Appeals thoroughly discussed expert testimony on the recognition of impairment by a trained law enforcement officer. The question in this case was whether the state needed to lay a foundation for its evidence against the defendant. The court said that the general expert testimony of the officer regarding his observations was not scientific and did not require a foundation to be laid, but the officer’s determination as to whether the defendant had passed or failed field sobriety tests *was* scientific and required a foundation. As such, the court overturned the defendant’s conviction for impaired driving, as the state did not lay a proper foundation for that testimony.


State v. Rambo, 279 P.3d 361 (Ct. App. Ore. 2012). In this case, the police officer's opinion that defendant had driven while under the influence was admissible as nonscientific expert opinion evidence, at trial of defendant on charge of driving under the influence of a controlled substance (DUII), where testimony was based on a foundation that included certain evidence that is encompassed in a drug recognition expert (DRE) test, even though evidence of the DRE protocol itself was inadmissible because officer had failed to complete protocol by failing to complete obtain the results of an analysis of the defendant's urine. The evidence showed that the officer was qualified, by virtue of considerable training and experience, to recognize the symptoms of drug impairment in the course of a DUII investigation, and the fact that officer reinforced his opinion in part on independently admissible scientific evidence, such as blood alcohol content and horizontal gaze nystagmus (HGN) test results, that were part of the DRE protocol did not render the officer’s opinion inadmissible as unqualified scientific evidence.


State v. Downing, 366 P.3d 1171 (Ct. App. Ore. 2016). In this case, the Court of Appeals of Oregon upheld a lower court decision that stated that an incompletely administered DRE protocol is not, itself, admissible as scientific evidence (citing State v. Sampson and State v Aman), but may still be admissible testimony. In the case, the state introduced certain portions of the DRE protocol as evidence by independently laying a foundation for the admission of each facet of the DRE protocol that it wished to have admitted. The court of appeals held that the trial court was not required to exclude all evidence that resulted from the incomplete 12-step DRE protocol.

State v. Burshia, 120 P.3d 487 (Ct. App. Ore. 2004). As interpreted in Oregon, for the DRE protocol and testimony to be admissible, all 12 steps of the protocol must be completed. In this case, in an interlocutory appeal, the state challenged the suppression of a breath test, which resulted in the exclusion of the DRE protocol and testimony. The appellate court remanded the case to the trial court for trial on the merits.

State v. McFarland, 191 P.3d 754 (Ct. App. Ore. 2008). In this case, the Court of Appeals of Oregon held that a DRE trainee was not qualified to give DRE testimony about the DRE protocol, that the trainee’s testimony should have been excluded, and that its admission was not harmless error. 

State v. Hernandez, 206 P.3d 197 (Ct. App. Ore. 2009). The DRE officer in this case did not collect a urine sample because the defendant refused. The appellate court stated the DRE protocol is "scientific evidence." The Court in this case expressed a willingness to admit the non-scientific aspects of the DRE test but the state failed to indicate which parts of the test they intended to use. This case falls squarely under Aman and is important because it identifies the Oregon response to the defendant's refusal to provide a sample.


State v. Bayer, 211 P.3d 327 (Ct. App. Ore. 2009). The defendant in this case challenged the method used to do the urine testing and argued that the deviation in the testing caused the DRE tests to be incomplete and inadmissible. The appellate court disagreed, reaffirming the logic of Sampson.

South Carolina

South Carolina v. Martin, 706 S.E.2d 40 (S.C. Ct. App. 2011). In this case, the South Carolina Court of Appeals allowed DRE testimony under South Carolina’s Rule 702 of Evidence, which is identical to the FRE of Evidence 702. The court did not identify whether the evidence was new or novel.  Additionally, the court performed a Frye/Daubert-type analysis on the testimony, but did not cite directly to either case.



Richter v. State, 482 S.W.3d 288 (Ct. App. Tex. 2015). In this case, the Texas Court of Appeals found that even though the state’s DRE was not certified at the time of the incident, but was certified by trial, the trial court did not abuse its discretion in allowing the state’s DRE to testify, as he was able to testify to his training and his methodology in developing his testimony. The court affirmed the defendant’s conviction.



Utah v. Layman, 953 P.2d 782 (Utah Ct. App. 1998). In this case, the Court of Appeals of Utah held that DRE testimony is not a scientific test. 


"Layman claims the trial court erred in admitting Deputy DeCamp's testimony regarding Layman's intoxication without first analyzing that testimony under the test set forth in State v. Rimmasch, 775 P.2d 388, 396-99 (Utah 1989). We agree with the State, however, that the Rimmasch analysis applies only to expert testimony based on scientifically derived facts or determinations, and not to an expert's personal observations and opinions based on his or her education, training, and experience. This court has held a Rimmasch analysis is required to determine "the admissibility of testimony based on an external scientific process or statistical profile." State ex rel. G.D., Jr. v. L.D., 894 P.2d 1278, 1284 (Utah Ct. App. 1995). Where the expert testimony is opinion testimony based on the witness's training and experience, Rimmasch is not applicable, "as there [is] no scientific process on which to apply such an analysis." Id.; see also Salt Lake City v. Garcia, 912 P.2d 997, 1000-01 (Utah Ct. App.) (finding no error where trial court allowed testimony on result of field sobriety test without entertaining Rimmasch analysis, and court specifically informed jury this was not scientific evidence but rather was "part of the basis of the arresting officer's opinion that the defendant was under the influence"), cert. denied, 919 P.2d 1208 (Utah 1996)."



State v. Baity, 991 P.2d 1151 (Wash. 2000). In this case, the Supreme Court of Washington held that the DRE Protocol is a novel scientific test and must be analyzed under Frye. The court determined the protocol and the testimony of the officer were admissible, provided that all 12 steps of the protocol are used.

"In summary, after analyzing the DRE protocol and the approach of other courts to its admissibility, we hold the DRE protocol and the chart used to classify the behavioral patterns associated with seven categories of drugs have scientific elements meriting evaluation under Frye. We find the protocol to be accepted in the relevant scientific communities. We emphasize, however, that our opinion today is confined to situations where all 12 steps of the protocol have been undertaken. Moreover, an officer may not testify in a fashion that casts an aura of scientific certainty to the testimony. The officer also may not predict the specific level of drugs present in a suspect. The DRE officer, properly qualified, may express an opinion that a suspect's behavior and physical attributes are or are not consistent with the behavioral and physical signs associated with certain categories of drugs."


But see State v. Mashek, 312 P.3d 774 (Ct. App. Wash. 2013). In this case, the Court of Appeals held that the trial court acted within its discretion in excluding State's proposed drug recognition expert testimony on defendant's motion in trial on charge of driving under the influence of alcohol (DUI), which testimony was offered to explain the results of defendant's field sobriety tests as evidence of her intoxication, where State was given opportunity to explain proposed testimony's value but failed to show how expert testimony would have been helpful to jury in light of testimony from police officer who was trained in administering field sobriety tests and actually performed defendant's tests, instead providing only bare assertion that expert would have been “better” at explaining the tests than officer.



State v. Chitwood, 879 N.W.2d 786 (Ct. App. Wis. 2016). In this case, the Court of Appeals of Wisconsin strongly endorsed the admissibility of DRE testimony. The court evaluated the use of DRE testimony under the Daubert standard, which was adopted by Wisconsin. In its opinion, the court laid out the twelve factors DREs consider, with a short explanation of each. The court established that the admissibility of such evidence is guided by Wisconsin’s parallel rule to FRE 702. The court then extensively describes the reliability of DRE testimony and therefore holds it to be admissible under the state’s evidentiary rule/Daubert standard. Based on the court’s strong endorsement of DRE testimony as reliable, the court upheld the defendant’s conviction.


City of Mequon v. Haynor, 791 N.W.2d 406 (2010) (unpublished). The defendant in this case did not directly challenge the scientific basis of the DRE testing. He argued that the testing was unreliable and the court disagreed. The court applied a simple relevancy test to the DRE evidence.

The Judicial Resource Center on Drug-Impaired Driving thanks Greg Hurley and the National Center for State Courts for their contributions to this page.

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