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Arizona DUI Case Law Update | February 2026
Arizona Appeals Court Vacates DUI Convictions Based on Non-Impairing Marijuana Metabolite
Here’s what happened, what the court decided, and why it matters to anyone navigating Arizona DUI law.
The Core Takeaway
Under Arizona law, a DUI based on a marijuana “metabolite” in your system is only valid if that metabolite is capable of causing impairment. A non-impairing metabolite called Carboxy-THC does not qualify — and a conviction resting solely on its presence cannot stand.
Background: What Happened in This Case?
The underlying events go all the way back to 1998 in Maricopa County. Stanley West was involved in a three-car collision while his three- and four-year-old sons were passengers in his vehicle. Officers at the scene observed signs consistent with drug impairment — bloodshot and watery eyes, tremors in his eyelids and body — and a drug recognition expert concluded West was impaired by marijuana.
West himself admitted to smoking marijuana about an hour before the accident, reportedly acknowledging he should have known better than to drive with his kids when he was high. A urine test came back positive for Carboxy-THC, a marijuana metabolite, and officers also found a pipe and small wooden box with marijuana in his pockets.
The State charged West with four counts of aggravated DUI — aggravated because his children (both under 15) were in the car. Two of the four counts were based on him driving while impaired to the slightest degree (one count per child). The other two were based on driving with marijuana or its metabolite in his body (again, one per child).
West was convicted on all four counts at trial in 1999 — but then he fled before sentencing and remained a fugitive for almost 25 years. After his arrest in 2024, he was placed on probation and filed this appeal.
What the Court Decided
The Court of Appeals reviewed four major issues raised by West. Here’s how it ruled on each:
- VacatedCounts 2 & 5 — Metabolite-Based DUI Convictions: The court threw out the two convictions based on driving with marijuana metabolite in West’s body. Carboxy-THC, the only metabolite identified in the record, is non-impairing and doesn’t satisfy Arizona’s DUI statute as interpreted by the Arizona Supreme Court. These counts were remanded for potential retrial.
- AffirmedCounts 1 & 4 — Impaired to the Slightest Degree: The court upheld the two convictions based on driving while actually impaired. Physical signs of impairment, the drug recognition expert’s evaluation, and West’s own admission at the scene supported these convictions despite missing trial transcripts.
- VacatedSentencing Order Error: The court also vacated language in the sentencing order suggesting West had been convicted and sentenced for marijuana possession and paraphernalia — charges that were dismissed with prejudice before sentencing.
- AffirmedEight-Person Jury: West argued his trial by an 8-person jury violated the Sixth Amendment. The court disagreed, reaffirming that an 8-person jury is constitutional in Arizona criminal cases not involving a sentence of 30+ years.
The Key Legal Issue: What Does Arizona’s DUI Metabolite Law Actually Say?
Arizona law makes it illegal to drive with a marijuana metabolite in your body. But what counts as a “metabolite”? That question was answered by the Arizona Supreme Court back in 2014 in State ex rel. Montgomery v. Harris (Shilgevorkyan).
“Metabolites that are capable of causing impairment” — that’s the standard the Arizona Supreme Court set. Carboxy-THC, the inactive breakdown product commonly detected in urine tests, doesn’t meet that bar.
Carboxy-THC is what remains in the body after THC — the psychoactive component of marijuana — has already been metabolized. It doesn’t cause impairment and can linger in the system for days or even weeks after use. In other words, someone could test positive for Carboxy-THC and be completely sober behind the wheel.
At West’s 1999 trial, the law wasn’t yet this clear. Courts at the time upheld convictions based on Carboxy-THC alone. But the law has since changed, and the appeals court applied the current, correct interpretation.
Why the Missing Transcripts Didn’t Sink the Whole Appeal
One of the more unusual aspects of this case was the near-total absence of trial transcripts from 1999. Court reporters had retired, one had died, and records were simply gone. West argued this alone entitled him to a new trial.
The court said no — at least not across the board. Under Arizona law, the absence of transcripts only warrants a new trial if the defendant can show a credible allegation of reversible error that can’t be resolved from the available record. For the impaired-to-the-slightest-degree counts, enough evidence existed elsewhere in the record to defeat that argument. For the metabolite counts, West succeeded because the only metabolite referenced anywhere in the available record was Carboxy-THC — and that’s not enough to sustain a conviction under current law.
What Does This Mean for Arizona DUI Cases Today?
If you’re facing a marijuana-related DUI charge in Arizona — or if someone you know is — this case reinforces several important points:
Testing positive for marijuana doesn’t automatically mean a DUI
Arizona prosecutors must distinguish between impairing and non-impairing metabolites. If the only substance detected is Carboxy-THC, a metabolite-based DUI charge is legally vulnerable. An experienced Arizona DUI defense attorney can scrutinize the lab results and challenge whether the right standard is being applied.
Old convictions can sometimes be revisited
This case involved events from 1998, yet the court still applied current law. If you or someone you know has an older marijuana-related DUI conviction in Arizona — particularly one based solely on metabolite presence — it may be worth having an attorney review whether it can be challenged.
Impairment evidence still matters — a lot
The two impaired-to-the-slightest-degree counts in this case survived. West’s own admission, physical symptoms, and the drug recognition expert’s assessment were enough. If the State can show actual impairment, a separate charge under A.R.S. § 28-1381(A)(1) can stand regardless of what metabolite is or isn’t in the blood or urine.
The rules are different for active THC
This ruling applies specifically to non-impairing metabolites like Carboxy-THC. Active THC — the compound that actually causes impairment — remains a basis for a valid DUI charge in Arizona.
Facing a Marijuana DUI Charge in Arizona?
The line between a defensible case and a conviction often comes down to the details — including exactly what was found in your system and whether it meets the legal threshold. If you have questions about your situation, it’s worth talking to someone who knows Arizona DUI law.
Case Summary at a Glance
State v. West, No. 1 CA-CR 24-0611 (Ariz. App. Feb. 6, 2026). The Arizona Court of Appeals vacated two aggravated DUI convictions (Counts 2 and 5) based on driving with a marijuana metabolite in the defendant’s body, where the only metabolite identified was Carboxy-THC — a non-impairing metabolite that does not satisfy Arizona’s DUI metabolite statute as interpreted by State ex rel. Montgomery v. Harris (Shilgevorkyan), 234 Ariz. 343 (2014). The court affirmed the remaining two convictions for driving while impaired to the slightest degree and remanded the vacated counts for potential retrial at the State’s option.
Legal Disclaimer: This blog post is for general informational purposes only and does not constitute legal advice. Reading this post does not create an attorney-client relationship. Arizona law is subject to change; always consult a licensed Arizona attorney regarding your specific situation.
