Driving While Intoxicated Case Law Update - Texas District ...

the defendant's BAC at the time of the collision was his height and weight, the type and
approximate number of drinks, the time of the crash and the time of the blood testwhich was about
two hours and 1 5 minutes after the crash. The expert uras a/so told to rely on certain assumpftbns
such as the time period over which he drank, when and what he last ate, the size of the beer
consumed, and the fact that defendant was a "social drinker." The Court held it was not error to
admit the extrapolation evidence.
Fulenwider v. State, 176 S.W.3d 290 (Tex.App.-Houston [1 Dist.] 2004, pet. ref'd).
The retrograde extrapolation expert had sufficient knowledge of defendant's characteristics and
behaviors to render reliable extrapolation of defendant's alcohol concentration at time of alleged
offense of DWl. The expert testified that shte did not know when defendant had her last drink, but
did know the time of offense, time that breath fesfs were conducted, and defendant's gender,
weight, height, and last meal, and expert had basis on which to determine time that defendant had
her last drink, given eyewitness testimony as to defendant's drinking prior to offense.
Peden v. State,2OO4WL2538274 (Tex.App.-Houston [1 Dist.] 2004, pdr ref'd).
Retrograde extrapolation was properly admitted in fhrs case based upon the expert's knowing the
following details. There was a single fesf resu/f an hour and forty-four minutes afterthe stop. She
knew defendant's weight and what he ate over a four hour period and that he did not have any
alcohol after 10:30which wasthirty-five minutes beforethe stop and an hour and nineteen minutes
before the test result of 0.12. Based on this the expert concluded that even if the defendant's
alcohol content had peaked at the time of testing, his alcohol concentration would have been over
0.08 at the time he drove his car.
Bhakta v. State, 124 S.W.3d 738 (Tex.App.-Houston [1 Dist.], 2A03, pdr ref'd).
The Court held that fhe Sfafe's expert was qualified to testify about retrograde extrapolation and
that he knew sufficient facts about the defendant to offer an opinion. ln so holding, the Court
sfressed fh at not every single personal fact about the defendant must be known to an expert giving
retrograde extrapolation testimony in a driving while intoxicated prosecution in order to produce an
extrapolation with the appropriate level of reliability. ln fhis case, the facts known to the Sfate's
expert were the time of his last drink, his weight and height, the time of the breath fesfs, fhe resu/fs
of the breath fesfs, his last meal prior to being stopped, and the time of that meal.
X. OPERATOR NEED NOT UNDERSTAND SCIENCE BEHIND THE INSTRUMENT!
Reynolds v. State, 204 S.W.3d 388 (Tex.Crim.App. 2006).
In response to the question of whether the breath test operator needed to understand the science
behind the instrument, the Court said: The fact of certification is sufficientto meetthe Kellv criteria
with respect to the competence of the breath test operator. That the opponent of the evidence can
demonstrate that the operator has not retained all of the knowledge that was required of him for
certification is a circumstance that goes to the weight, not the admissibility, of the breath test
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