State of Iowa v. Erik Milton Childs, 2017 Iowa Sup. LEXIS 77

Around 9:41 p.m., Deputy Weber stopped Erik Childs for expired registration and observed the car crossing the centerline; Childs admitted to smoking half a joint and showed signs of impairment during field sobriety tests.
Childs consented to a urine test; it detected 62 ng/mL of carboxy-THC, a non‑impairing metabolite of THC.
Childs was charged under Iowa Code § 321J.2(1)(a) and (c); he moved to dismiss arguing Comried (Iowa precedent) should be overruled because later Arizona authority narrowed Phillips.
The district court denied the motion to dismiss (framing the argument as a constitutional one) and denied suppression of the stop; Childs was convicted and appealed; the court of appeals affirmed; the Iowa Supreme Court granted further review limited to the statutory‑interpretation issue.
The Supreme Court reaffirmed State v. Comried and held Iowa’s per se provision (§321J.2(1)(c)) criminalizes driving with any detectable amount of a controlled substance or its metabolite in the body, including non‑impairing metabolites like carboxy‑THC; no constitutional challenge was decided.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Iowa Code § 321J.2(1)(c) encompasses non‑impairing metabolites (i.e., whether Comried should be overruled)	Childs: Comried relied on Phillips (AZ); Phillips was later narrowed by Harris, so Iowa should exclude non‑impairing metabolites from § 321J.2(1)(c)	State: § 321J.2(1)(c) plainly bans driving with “any amount” of a controlled substance or any metabolite; legislature included metabolites explicitly; Comried stands	Court reaffirmed Comried: plain statutory text and definitions include metabolites; conviction may rest on non‑impairing metabolite alone (no constitutional challenge resolved)
Whether error on statutory interpretation was preserved for review	Childs: argued in district court that Comried is no longer good law; preserved the statutory claim	State/district court: district court treated the argument as constitutional but the appellate record reflects the statutory argument was presented and preserved	Court held error was preserved and proceeded to decide the statutory question
Lawfulness of the traffic stop and chemical test (suppression)	Childs: argued stop/test lacked reasonable suspicion/probable cause	State: stop justified by expired registration and crossing centerline; officer observed impairment and admission to marijuana use	Court of appeals’ affirmance of denial of suppression stands; stop and urinalysis were lawful

State v. Comried, 693 N.W.2d 773 (Iowa 2005) (interpreting §321J.2(1)(c) to prohibit driving with any detectable amount of a controlled substance)
State v. Phillips, 873 P.2d 706 (Ariz. Ct. App. 1994) (Arizona appellate decision relied on in Comried)
State ex rel. Montgomery v. Harris, 322 P.3d 160 (Ariz. 2014) (Arizona Supreme Court narrowed Phillips; held non‑impairing metabolites alone cannot sustain DUI conviction)
Bearinger v. Iowa Dep’t of Transp., 844 N.W.2d 104 (Iowa 2014) (discussing prescription‑drug defense and interpreting related statutory context)
Loder v. Iowa Dep’t of Transp., 622 N.W.2d 513 (Iowa Ct. App. 2000) (court of appeals reasoning on difficulty linking metabolite levels to impairment)
People v. Derror, 715 N.W.2d 822 (Mich. 2006) (Michigan Supreme Court holding carboxy‑THC is a derivative/metabolite of THC)
People v. Feezel, 783 N.W.2d 67 (Mich. 2010) (overruling Derror and narrowing the scope of metabolites as controlled substances)
State v. Adams, 810 N.W.2d 365 (Iowa 2012) (requiring causal link between intoxication and resulting harm in vehicular homicide)