State v. TurbyfillÂ, 243 N.C. App. 183

On Dec. 21, 2011 defendant Christopher Turbyfill crashed his truck; officers observed slurred speech, bloodshot eyes, unsteadiness, and smell of alcohol; defendant admitted drinking and taking Xanax and hydrocodone.
Officer Lovelace administered SFSTs (HGN, walk‑and‑turn, one‑leg stand); as HGN expert he testified to 6/6 HGN clues and equated certain HGN clues with a .10+ BAC.
Defendant registered a .07 breathalyzer less than two hours after the crash.
State’s expert Anthony Burnette (DHHS Forensic Test for Alcohol Branch) was qualified after voir dire as an expert in blood alcohol physiology/pharmacology and retrograde extrapolation; he used an elimination rate of .0165/hr and calculated a retrograde BAC of .10 at the time of the crash.
A jury convicted defendant of DWI and driving after consuming alcohol under 21; defendant appealed, arguing (I) Burnette should not have been qualified as an expert and (II) plain error from Officer Lovelace’s testimony about BAC from HGN.

Issue	State's Argument	Turbyfill's Argument	Held
Admissibility of Burnette's retrograde extrapolation testimony	Burnette has sufficient knowledge, experience, training, publications, and prior case work to be qualified; methods are generally accepted and reliable	Burnette lacked sufficient scientific/mathematical grounding under amended Rule 702/Daubert; misused terms ("midpoint" v. "average") and failed to justify reliability	Court affirmed qualification; trial court did not abuse discretion in admitting Burnette's expert opinion
Officer Lovelace testifying to BAC based on HGN	Testimony assisted jury on impairment; officer qualified to give HGN impairment opinion	Testimony improperly stated specific BAC from HGN in violation of Rule 702(a1) and thus prejudiced defendant	Court found HGN testimony technically violated Rule 702(a1) as to stating BAC level, but any error was not plain error given ample independent evidence (admission, conduct, breath test, Burnette's extrapolation)

State v. Hennis, 323 N.C. 279, 372 S.E.2d 523 (defining abuse of discretion standard)
State v. Bullard, 312 N.C. 129, 322 S.E.2d 370 (trial court's wide latitude on expert admissibility)
Howerton v. Arai Helmet, Ltd., 358 N.C. 440, 597 S.E.2d 674 (framework for admissibility of expert testimony)
State v. Taylor, 165 N.C. App. 750, 600 S.E.2d 483 (discussing conservative elimination rate (.0165) and retrograde extrapolation in NC)
State v. Catoe, 78 N.C. App. 167, 336 S.E.2d 691 (upholding use of extrapolation)
State v. Fuller, 176 N.C. App. 104, 626 S.E.2d 655 (retrograde extrapolation precedent)
State v. Teate, 180 N.C. App. 601, 638 S.E.2d 29 (retrograde extrapolation precedent)
State v. Davis, 142 N.C. App. 81, 542 S.E.2d 236 (retrograde extrapolation precedent)