In a recent ruling, the Oregon Court of Appeals upheld the conviction of Trenton Coba Morris for driving under the influence of intoxicants (DUII). The court's decision, filed on November 12, 2026, confirms the jury's verdict and the trial court's sentencing of Morris to three days in jail and 24 months of bench probation. This case is significant as it addresses the admissibility of scientific evidence and the obligations of prosecutors in disclosing expert testimony.

The case, State v. Morris (A186463), began when Morris was charged with DUII after a traffic stop. The prosecution presented evidence from a horizontal gaze nystagmus (HGN) test, which is commonly used to determine impairment due to alcohol. Morris contested the validity of the HGN test results, arguing that one component of the test was improperly administered and that the prosecution failed to disclose critical expert testimony regarding retrograde extrapolation calculations.

The parties involved in this case include the State of Oregon as the plaintiff and Trenton Coba Morris as the defendant. The case reached the Court of Appeals after Morris appealed his conviction, claiming errors in the trial court's handling of evidence and discovery issues. The appeal focused on two main arguments: the admissibility of the HGN test results and the alleged failure of the prosecution to disclose expert testimony related to blood alcohol content (BAC) calculations.

The Court of Appeals, led by Judge Jacquot, reviewed the trial court's decisions regarding the HGN test and the discovery violation claims. The court found that the trial court had appropriately admitted the properly administered portions of the HGN test while excluding the improperly administered part. Judge Jacquot stated, "The presence of the four clues in the first two phases adequately supported the scientific assertion that the HGN was offered to prove." This ruling indicates that even if one part of a scientific test is flawed, the remaining valid portions can still be considered as evidence.

Regarding the second assignment of error, the court addressed Morris's claim that the prosecution's failure to disclose the expert's retrograde extrapolation calculation constituted a discovery violation. The trial court had ruled that there was no violation since the prosecutor did not possess any written reports or materials related to the extrapolation prior to the trial. The Court of Appeals affirmed this decision, stating that the trial court did not err in concluding that no discovery violation had occurred.

The ruling emphasized that retrograde extrapolation is a common aspect of DUI cases and that the defense should have been aware of its potential use. The court noted that even if there had been a discovery violation, the appropriate remedy would not have involved excluding the expert's testimony but rather allowing the defense time to prepare.

This decision has implications for future DUII cases in Oregon, particularly regarding the handling of scientific evidence and the responsibilities of prosecutors in disclosing expert testimony. The ruling reinforces the idea that not all errors in administering tests will automatically invalidate the results, as long as sufficient valid evidence remains.

Looking ahead, it is unclear whether Morris will seek further appeal options. The court's ruling is final in this instance, as it is a nonprecedential opinion, meaning it cannot be cited as legal precedent in future cases. However, the case highlights ongoing discussions about the standards for scientific evidence in DUII prosecutions and the importance of proper disclosure practices in the legal process.