People v. Mumaugh, 94 N.E.3d 237

On June 21, 2012, at ~10:30 p.m. on an unlit rural road, Brandon Mumaugh (driver) struck 12‑year‑old pedestrian Jennifer Dennis; she suffered great bodily harm and permanent disabilities.
Mumaugh was driving ~50 mph (posted 55), headlights working; the pedestrian was wearing dark clothing and was walking near or in the center of the road; an eyewitness had called 911 minutes earlier reporting two girls walking on the blacktop.
Police administered field sobriety tests at the scene; officers observed no signs of impairment and detected no odor of cannabis; Mumaugh admitted smoking marijuana five days earlier.
A “hitter” pipe with a DNA mixture including Mumaugh’s profile and trace cannabis was found at the scene; urine testing detected an undetermined quantity of a THC metabolite.
Mumaugh was convicted after a stipulated bench trial of aggravated DUI under the 2012 version of 625 ILCS 5/11‑501(a)(6) and (d)(1)(C) (strict‑liability possession of any THC in bodily fluid plus accident causing great bodily harm) and sentenced to two years; he appealed arguing insufficient proximate cause and facial unconstitutionality of the statute.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether State proved defendant’s driving was a proximate cause of victim’s injuries	Driving was a proximate cause because an accident occurred while defendant had cannabis metabolite in his system; driving itself created the causal link	Victim’s unforeseeable conduct (walking in dark, unlit road in dark clothes near center line) was the sole proximate cause; defendant’s driving was non‑negligent and not a legal cause	Reversed: State failed to prove proximate cause; evidence showed victim’s conduct was the unforeseeable intervening cause
Whether the 2012 strict‑liability aggravated‑DUI statute is facially unconstitutional as substantive due‑process overcriminalization	(State did not press constitutional argument on appeal given reversal on other grounds)	Statute criminalizes innocent conduct (any THC amount) and is not rationally related to removing drug‑impaired drivers	Court did not reach the constitutional challenge because reversal on proximate‑cause ground rendered it unnecessary

People v. Fate, 159 Ill.2d 267 (1994) (upholding strict‑liability drug‑driving provision and presumption of impairment)
First Springfield Bank & Trust v. Galman, 188 Ill.2d 252 (1999) (proximate‑cause analysis: distinction between condition and legal cause; foreseeability test)
Reuter v. Korb, 248 Ill. App. 3d 142 (1993) (similar facts; pedestrian’s conduct was sole proximate cause when pedestrian suddenly entered roadway at night)
People v. Quigley, 183 Ill.2d 1 (1998) (explaining aggravated DUI is misdemeanor DUI plus aggravating factors)
People v. Hudson, 222 Ill.2d 392 (2006) (cause in fact and legal cause are elements of proximate cause)