People v. Floyd
2014 IL App (2d) 120507
Ill. App. Ct.2014Background
- Floyd was convicted of aggravated DUI and resisting arrest after a jury trial.
- The State introduced a retrograde extrapolation expert to show Floyd’s BAC was at or above 0.08 at the time of arrest, based on a 0.069 BAC breath test at 10:30 p.m.
- Extrapolation assumed elimination of alcohol and used a fixed rate, with numerous contributing factors unknown.
- The expert admitted uncertainly about Floyd’s eating, drinking patterns, last drink timing, and other personal factors; only a single BAC test was performed.
- Defense challenged the extrapolation’s reliability and prejudicial effect; trial admitted the extrapolation, other-crimes evidence, and certain HGN testimony.
- The appellate court reversed Floyd’s DUI conviction and remanded for a new trial, finding the extrapolation evidence unreliable and prejudicial.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Admissibility of retrograde extrapolation | State contends calculation reliable despite unknown factors | Floyd argues calculation unreliable and prejudicial | Extrapolation evidence is inadmissible; prejudicial value outweighs probative value |
| Admission of other-crimes evidence | State argues relevance and admissibility | Floyd argues highly prejudicial and minimally relevant | Not reviewed |
| Foundation for HGN testimony | State presented HGN testimony without complete foundation | Floyd challenges foundation of HGN | Not reviewed |
| Video evidence and jury instruction about it | State argues video evidence was properly admitted | Floyd contends jury should not infer from video not produced | Not reviewed |
| Frye standard and admissibility | Frye framework governs admissibility of scientific evidence | Frye does not require preclusion if probative value is high | Frye does not mandate exclusion; balancing governs admissibility |
Key Cases Cited
- Armstrong v. Eighth Judicial Dist. Court, 267 P.3d 777 (Nev. 2011) (retrograde extrapolation requires many known factors; single test is unreliable)
- Mata v. State, 46 S.W.3d 902 (Tex. Crim. App. 2001) (multiple tests can permit reliable extrapolation with limited personal data)
- Petraski v. Thedos, 382 Ill. App. 3d 22 (Ill. App. 2008) (retrograde extrapolation debated; potential for substantial prejudice)
- People v. McKown, 236 Ill. 2d 278 (Ill. 2010) (balancing probative value against unfair prejudice in scientific evidence)
- People v. Lopez, 229 Ill.2d 322 (Ill. 2008) (double-checking standard for admissibility and sufficiency of evidence)
- In re Commitment of Simons, 213 Ill.2d 523 (Ill. 2004) (Frye-related admissibility framework referenced)