In this Robeson County case, defendant appealed his conviction for driving while impaired, arguing the trial court erred by admitting a toxicology report without authentication and allowing the arresting officer to testify to defendant’s specific blood alcohol concentration. The Court of Appeals found no prejudicial error by the trial court.

In September of 2018, defendant was stopped by an officer due to a partially obstructed license plate; after stopping defendant, the officer noticed glassy eyes and slurred speech, leading to a horizontal gaze and nystagmus (“HGN”) test. Defendant performed poorly on the test, and a later toxicology blood test found that defendant’s blood alcohol concentration was 0.27. At trial, the arresting officer testified about the results of the HGN test, saying “[t]here’s a probability that he’s going to be a .08 or higher, 80% according to the test that was done.” Slip Op. at 3. Also during the trial, the SBI agent responsible for preparing the report on defendant’s toxicology test was not available to testify, so another agent performed an administrative and technical review of the report and was permitted to testify as an expert about the results. The report was admitted despite defendant’s objection.

Reviewing defendant’s appeal, the court first noted that Rule 703 of the North Carolina Rules of Evidence does not require the testifying expert to be the person who performed the test, explaining “[a]n expert may properly base his or her opinion on tests performed by another person, if the tests are of the type reasonably relied upon by experts in the field.” Id. at 5, quoting State v. Fair, 354 N.C. 131, 162 (2001). Here the report was admitted as the basis of the testifying expert’s opinion, not as substantive evidence, within the scope of applicable precedent around Rule 703. The court also noted that defendant had ample opportunity to cross-examine the expert on the basis of her opinion and her credibility in front of the jury, avoiding any confrontation clause issues.

The court found that admitting the arresting officer’s testimony regarding defendant’s specific blood alcohol level after conducting an HGN test was error, but harmless error. There are two bases under G.S. § 20-138.1 to convict a defendant for impaired driving; subsection (a)(1) and (a)(2) are distinct and independent grounds for conviction of the same offense. Id. at 10, citing State v. Perry, 254 N.C. App. 202 (2017). The court noted that overwhelming evidence of both prongs was present in the record, and specifically the second prong, driving with an alcohol concentration of 0.08 or more, was supported by expert testimony unrelated to the officer’s testimony. Finding no reasonable possibility the jury could have reached a different conclusion, the court upheld the verdict.

In this DWI case the trial court did not abuse its discretion by admitting an officer’s expert testimony that the defendant was under the influence of a central nervous system depressant. On appeal the defendant argued that the State failed to lay a sufficient foundation under Rule 702 to establish the reliability of the Drug Recognition Examination to determine that alprazolam was the substance that impaired the defendant’s mental or physical faculties. The defendant also argued that the officer’s testimony did not show that the 12-step DRE protocol was a reliable method of determining impairment. The court rejected these arguments, noting that pursuant to Rule 702(a1)(2), the General Assembly has indicated its desire that Drug Recognition Evidence, like that given in the present case, be admitted and that this type of evidence already has been determined to be reliable and based on sufficient facts and data. Accordingly, the trial court properly admitted the testimony. 

Following its decision in State v. Babich, ___ N.C. App. ___, 797 S.E.2d 359 (2017), in this DWI case the court held that the State’s expert testimony regarding retrograde extrapolation was inadmissible under Daubert and Rule 702. The expert used the defendant’s .06 BAC 1 hour and 35 minutes after the traffic stop to determine that the defendant had a BAC of .08 at the time of the stop. To reach this conclusion the expert assumed that the defendant was in a post-absorptive state at the time of the stop, meaning that alcohol was in the process of being eliminated from his bloodstream and that his BAC was in decline. The expert admitted that while there were no facts to support this assumption, it was required so that he could complete his retrograde extrapolation analysis. The State conceded error under Babich and argued only that the error was not prejudicial. The court found otherwise and reversed and remanded for a new trial.

The trial court did not commit plain error by allowing a trooper to testify at trial about the HGN test he administered on the defendant during the stop where the State never formally tendered the trooper as an expert under Rule 702. The court noted that during the pendency of the appeal the state Supreme Court decided State v. Godwin, ___ N.C. ___, ___ 800 S.E.2d 47, 48 (2017) (Evidence Rule 702(a1) does not require a law enforcement officer to be recognized explicitly as an expert witness pursuant to Rule 702 before the officer may testify to the results of a HGN test), which controls this case. As in Godwin, the defendant was not arguing that the officer was unqualified to testify as an expert, but only that he had to be formally tendered as such. Under Godwin “it was simply unnecessary for the State to make a formal tender of the trooper as an expert on HGN testing.”

In this DWI case, the trial court erred by admitting retrograde extrapolation testimony by the State’s expert witness. That expert used the defendant’s 0.07 blood alcohol concentration 1 hour and 45 minutes after the traffic stop to extrapolate that the defendant had a blood alcohol concentration of 0.08 to 0.10 at the time of the stop. To reach this conclusion, the expert assumed that the defendant was in a post-absorptive state at the time of the stop, meaning that alcohol was no longer entering the defendant’s bloodstream and thus her blood alcohol level was declining. The expert conceded that there were no facts to support this assumption. The expert made this assumption not because it was based on any facts in the case, but because her retrograde extrapolation calculations could not be done unless the defendant was in a post-absorptive state. The expert’s testimony was inadmissible under the Daubert standard that applies to Evidence Rule 702. The court added: “Although retrograde extrapolation testimony often will satisfy the Daubert test, in this case the testimony failed Daubert’s ‘fit’ test because the expert’s otherwise reliable analysis was not properly tied to the facts of this particular case.” It explained:

[W]hen an expert witness offers a retrograde extrapolation opinion based on an assumption that the defendant is in a post-absorptive or post-peak state, that assumption must be based on at least some underlying facts to support that assumption. This might come from the defendant’s own statements during the initial stop, from the arresting officer’s observations, from other witnesses, or from circumstantial evidence that offers a plausible timeline for the defendant’s consumption of alcohol.

         When there are at least some facts that can support the expert’s assumption that the defendant is post-peak or post-absorptive, the issue then becomes one of weight and credibility, which is the proper subject for cross-examination or competing expert witness testimony. But where, as here, the expert concedes that her opinion is based entirely on a speculative assumption about the defendant—one not based on any actual facts—that testimony does not satisfy the Daubert “fit” test because the expert’s otherwise reliable analysis is not properly tied to the facts of the case.

The court went on to find that in light of the strength of the State’s evidence that the defendant was appreciably impaired, the error was not prejudicial.

Following its opinion in Godwin, above, the court held, in this DWI case, that the trial court erred by admitting lay opinion testimony on the results of an HGN test and that a new trial was required.

(1) The trial court did not abuse its discretion by qualifying the State’s witness as an expert in the fields of forensic blood alcohol physiology and pharmacology, breath and blood alcohol testing, and the effects of drugs on human performance and behavior. The witness was the head of the Forensic Test for Alcohol branch of the N.C. Department of Health and Human Services, oversaw the training of law enforcement officers on the operation of alcohol breath test instruments and of drug recognition experts. His specialty is in "scientific issues related to breath testing and blood testing for drugs and alcohol." He has a B.A. and master's in biology and is certified as a chemical analyst. He attended courses on the effects of alcohol on the human body and various methods for determining alcohol concentrations and the effects of drugs on human psychomotor performance. He has published several works and has previously been qualified as an expert in forensic blood alcohol physiology and pharmacology, breath and blood alcohol testing, and the effects of drugs on human performance and behavior over 230 times in North Carolina. Despite his lack of a formal degree or certification in physiology and pharmacology, his extensive practical experience qualifies him to testify as an expert. (2) The trial court did not abuse its discretion by admitting the State’s expert’s testimony regarding the relative amount of cocaine in the defendant's system at the time of the collision and the effects of cocaine on an individual's ability to drive. The defendant argued that the testimony was based upon unreliable methods. Based on cocaine’s half-life and a report showing unmetabolized cocaine in the defendant’s system, the expert determined that the defendant had recently used cocaine and that the concentration of cocaine in his system would have been higher at the time of the crash. On cross-examination, he testified that there was no way to determine the quantity of cocaine in the defendant's system. He further testified as to the effects of cocaine on driving ability, noting a correlation between "high-risk driving, speeding, [and] sometimes fleeing . . . when cocaine is present." He based this testimony on a study which "looked at crashes and behaviors and found [an] association or correlation between the presence of cocaine and high-risk driving." He testified that it was possible for cocaine to be detected in a person's system even after the person was no longer impaired by the drug. The expert’s testimony that the level of cocaine in the defendant's system would have been higher at the time of the collision and his testimony as to the general effects of cocaine on a person's ability to drive was supported by reliable methods. Notably, the defendant's expert corroborated this testimony both as to the half-life of cocaine and the existence of studies showing a correlation between the effects of cocaine and "high-risk" driving.

(1) In an impaired driving case, the trial court did not abuse its discretion by allowing the State’s witness to testify as an expert in pharmacology and physiology. Based on his knowledge, skill, experience, training, and education, the witness was better informed than the jury about the subject of alcohol as it relates to human physiology and pharmacology. (2) The court rejected the defendant’s argument that the trial court erred by allowing the expert to give opinion testimony regarding the defendant’s post-driving consumption of alcohol on grounds that such testimony was an opinion about the truthfulness of the defendant’s statement that he consumed wine after returning home. The court concluded that because the expert’s testimony was not opinion testimony concerning credibility, the trial court did not err by allowing the expert to testify as to how the defendant’s calculated blood alcohol content would have been altered by the defendant’s stated post-driving consumption; the expert’s statements assisted the jury in determining whether the defendant’s blood alcohol content at the time of the accident was in excess of the legal limit. (3) The trial court did not abuse its discretion by admitting the expert’s opinion testimony regarding retrograde extrapolation in a case where the defendant asserted that he consumed alcohol after driving. The defendant’s assertions of post-driving alcohol consumption went to the weight of the expert’s testimony, not its admissibility.

In a DWI/homicide case, the trial court erred by allowing a state’s witness to testify about ingredients and effect of Narcan. Although the state proffered the testimony as lay opinion, it was actually expert testimony. When the state called the witness, it elicited extensive testimony regarding his training and experience and the witness testified that Narcan contains no alcohol and has no effect on blood-alcohol content. Because the witness offered expert testimony and because the state did not notify the defendant during discovery that it intended to offer this expert witness, the trial court erred by allowing him to testify as such. However, the error was not prejudicial.