Two recent North Carolina Court of Appeals opinions help delineate when an officer has probable cause to believe a driver is driving while impaired. In each case, the court of appeals reversed the trial court’s determination that the officer lacked probable cause.
retrograde extrapolation
The Light Just Turned Yellow for Retrograde Extrapolation
I wrote in September 2015 that the court of appeals’ view of the admissibility of retrograde extrapolation under Daubert did not look much different from its take on the admissibility of that evidence under old Rule 702. As of yesterday, it does. The court of appeals in State v. Babich, __ N.C. App. __ (2017), changed the green light for retrograde extrapolation testimony in DWI cases to yellow.
Daubert Doesn’t Look Much Different from Howerton When it Comes to Retrograde Extrapolation
The court of appeals gave the green light last week for law enforcement officers to continue to testify as scientific experts in DWI cases involving retrograde extrapolation–notwithstanding the legislature’s amendment of Rule 702 to adopt the Daubert standard. The court held in State v. Turbyfill that a field technician for the Forensic Test for Alcohol Branch of DHHS (FTA), who was trained as a law enforcement officer and chemical analyst (which authorized him to conduct implied consent testing on breath testing instruments), was properly allowed to testify about a retrograde extrapolation calculation he performed using an FTA form. The technician’s inability to explain whether the rate he used to make the calculation was an “average,” a “mid-point,” or a “conservative” rate—he used all three terms to describe it—did not disqualify him as an expert since he “provided the trial court with a list of some thirty-nine articles . . . regarding blood alcohol research,” and “with North Carolina cases in which this Court upheld the use of retrograde extrapolation to establish blood alcohol content.”
Retrograde Extrapolation Alive and Well
I wrote here about the court of appeals’ decision in State v. Davis, __ N.C. App. __, 702 S.E.2d 507 (2010), granting the defendant a new trial on second degree murder, impaired driving and other charges arising from a fatal hit-and-run committed by the defendant after she had been drinking. Davis determined that expert testimony … Read more
The Nose Doesn’t Always Know: Extrapolation Based on Odor Ruled Unreliable
The Court of Appeals decided State v. Davis, 208 N.C. App. 26 (2010), last week, granting the defendant a new trial on second-degree murder, impaired driving and other charges arising from a fatal hit-and-run committed by the defendant after she had been drinking. While several aspects of the court’s opinion are noteworthy, this post focuses … Read more