Wisconsin Court of Appeals
Motor Vehicles – OWI – evidence — retrograde extrapolation testimony
David A. Thompson was convicted in municipal court for the City of Port Washington of operating a motor vehicle while under the influence of an intoxicant (OWI) and operating with a prohibited alcohol concentration (PAC) pursuant to Wis. Stat. § 346.63(1)(a) and (b). Thompson appealed to the circuit court on the issue of whether his blood alcohol concentration (BAC) was above .15, and the jury found that it was. Thompson now challenges this finding, arguing that expert testimony used at trial was inadmissible due to a lack of foundation. We hold that it was not an erroneous exercise of discretion for the circuit court to admit the testimony. Thompson’s objection to the expert’s retrograde extrapolation testimony—calculating backwards in time from a blood test to estimate the defendant’s BAC at the time of driving—goes to the testimony’s weight, not its admissibility. Affirmed. This opinion will not be published.
Dist II, Ozaukee County, Williams, J., Neubauer, P.J.
Attorneys: For Appellant: Piel, Walter Arthur, Jr., Milwaukee; For Respondent: Eberhardt, Eric E., Port Washington