People v. Moriarty — Michigan Court of Appeals affirmed an intoxicated-driving-causing-death conviction

Case
People of the State of Michigan v. Michael Shaun Moriarty
Court
Michigan Court of Appeals
Judge
Mark T. Boonstra (Rick Snyder, 2012); Adrienne N. Young (Gretchen Whitmer, 2024); Daniel S. Korobkin (Gretchen Whitmer, 2025)
Date Decided
August 10, 2026
Docket No.
376028
Topics
Drunk Driving, Proximate Cause, Sufficiency of Evidence, Great Weight of Evidence
Source
Read the full opinion

Background

Michael Shaun Moriarty was driving on a dark rural road in Van Buren County when his Toyota RAV4 struck and killed Todd Mullin, who was at the roadway’s edge with a disabled motorcycle. Moriarty admitted consuming six or seven beers, and the parties stipulated that his blood-alcohol content was 0.18% at the time of the collision. Mullin was wearing dark clothing and had alcohol, THC, and methamphetamine in his system.

The parties’ accident-reconstruction experts disagreed about whether the collision was avoidable. The prosecution’s expert testified that Moriarty could have changed lanes or swerved, while the defense expert concluded that even a sober driver would not have had enough time to react. A jury convicted Moriarty of operating while intoxicated causing death, and the trial court denied his motions for judgment notwithstanding the verdict and for a new trial.

The Court’s Holding

The Michigan Court of Appeals held that sufficient evidence supported the causation element of Moriarty’s conviction. Viewing the evidence in the prosecution’s favor, a rational jury could find that Mullin’s conduct—including his intoxication, dark clothing, and presence with a disabled motorcycle near the shoulder—amounted at most to ordinary negligence rather than gross negligence or intentional misconduct. It therefore did not constitute a superseding cause that broke the causal chain between Moriarty’s driving and Mullin’s death.

The court distinguished precedent requiring a jury to hear evidence of a victim’s intoxication because Moriarty’s jury received that evidence and was properly permitted to decide its significance. The jury could credit the prosecution’s expert over the defense expert and find it reasonably foreseeable that a rural road would be dark and that a disabled vehicle could be near the shoulder. Moriarty waived any challenge to the causation instructions by expressly approving them, and the court also held that the trial court did not abuse its discretion by rejecting his great-weight-of-the-evidence claim.

Key Takeaways

  • A victim’s intoxication or negligence does not automatically become a superseding cause; the jury must determine whether the conduct was unforeseeable gross negligence or intentional misconduct.
  • Conflicting expert testimony about whether a fatal collision was avoidable presents a credibility question for the jury.
  • Express approval of jury instructions waives an appellate challenge to their complexity or accuracy.

Why It Matters

The decision reinforces the deferential review applied to causation findings in operating-while-intoxicated-causing-death prosecutions. When the jury hears evidence of the victim’s impairment and conduct, an appellate court will not reweigh that evidence or substitute its assessment of competing experts.

It also clarifies that evidence sufficient to raise a superseding-cause question does not compel a finding for the defendant. Ordinary, reasonably foreseeable negligence by the victim does not sever proximate causation.

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