Whether substantial, competent evidence supported the jury's finding that Oliver drove while under the influence of alcohol and/or drugs.
Holding
Yes. The evidence permitted a reasonable jury to find beyond a reasonable doubt that alcohol and prescription drugs influenced or affected Oliver's driving.
Reasoning
The Court reviewed the verdict in the light most favorable to the prosecution. It would not reweigh evidence, reassess witness credibility, or replace the jury's reasonable inferences with its own. Under Idaho's DUI statute, the State did not have to prove that Oliver's alcohol concentration exceeded 0.08; it had to show that alcohol, drugs, or their combination affected his driving.
Oliver's driving itself supplied important evidence of impairment. A witness saw his pickup cross traffic lanes, travel in the center turn lane, drift into oncoming traffic, and move in a quick, jerky, erratic manner. He then struck another vehicle five times in slow traffic, including once after backing up, while seeming unaware of the collisions.
The physical and expert evidence reinforced the inference of impairment. Oliver had alcohol on his breath, admitted drinking a sixteen-ounce beer, displayed all six clues on the horizontal gaze nystagmus test, and performed the backward-counting task incorrectly. Although his breath-alcohol result was only 0.03, his urine contained several central-nervous-system depressants, including oxycodone, and a drug-recognition detective concluded that he was under the influence of a depressant and narcotic analgesic.
Pharmacist testimony explained why the combination mattered. The medications could cause drowsiness, confusion, disorientation, diminished coordination, and slower reactions; their effects were additive, and even a small amount of alcohol could increase those effects. The jury was entitled to reject Oliver's alternative explanations—that oversized work boots caused his driving problems, that the medications had worn off, and that traffic distractions caused his counting error.