Wisconsin Jury Instruction 2663 states, "If you are satisfied beyond a reasonable doubt that there was .08 (breath)
(blood) at the time the test was taken, you may find from that fact alone that the defendant was under the influence of an intoxicant or operating with a prohibited blood alcohol content at the time of the alleged operating, but you are not required to do so . . ." This instruction allows prosecutors to tell jurors, "I don't have to PROVE the defendant was actually impaired or .08 at the time of driving. If you, the jurors, believe the test demonstrates a BAC or .08 or greater AT THE TIME OF TEST, then 'the law' says you can also find he/she was impaired or .08 AT THE TIME OF DRIVING." It must be nice to play make believe and have the full force of the Wisconsin statutes to uphold the illusion.
Why is this so unfair? First, the test result "is admissible", so long as it was taken within 3 hours of the driving. This means, essentially, that no matter what the issues with the test--i.e. eight breath samples to get a good test--the test is admissible. Why? The Wisconsin statutes say so. This means the Judge at an OWI trial can't exclude a test taken within 3 hours of driving unless the test is so devoid of trustworthiness as to lack relevance altogether.
The other reason it's unfair is that the test result could be markedly higher than it was at the time of driving, because of the delay in full absorption of ethanol into the blood. The Wisconsin Jury Instructions state that the prosecution has the burden to prove each element of the offense of OWI or PAC. One of the two elements for OWI is that the driver was impaired at the time of driving. One of the two elements of PAC is that the driver had a BAC of .08 at the time of driving. But the same Jury Instructions say that impairment or BAC of .08 can be viewed as proven by a test of .08 or greater taken as long as 3 hours after driving. A BAC test taken any time later is almost certainly not the same as BAC at the time of driving.
So does the prosecution have to prove impairment or BAC at the time of driving or not? Apparently not. Is the jury allowed to pretend that BAC at the time of driving is the same as the time of test? Yes. In fact, they are strongly encouraged to do so if this jury instruction is allowed.
Fortunately, an experienced OWI attorney can often keep Wisconsin Jury Instruction 2663 out of the trial by the introduction of BAC "curve" evidence--i.e., evidence that BAC was below the legal limit at the time of driving, but rose above the legal limit after the driving. This type of defense will definitely help level the playing field.
885.235 (1g) states: In any action or proceeding in which it is material to prove that a person was under the influence of an intoxicant or had a prohibited alcohol concentration or a specified alcohol concentration while operating or driving a motor vehicle . . . evidence of the amount of alcohol in the person's blood at the time in question, as shown by chemical analysis of a sample of the person's blood or urine or evidence of the amount of alcohol in the person's breath, is admissible on the issue of whether he or she was under the influence of an intoxicant or had a prohibited alcohol concentration or a specified alcohol concentration if the sample was taken within 3 hours after the event to be proved. The chemical analysis shall be given effect as follows without requiring any expert testimony as to its effect:
* * *
(c) The fact that the analysis shows that the person had an alcohol concentration of 0.08 or more is prima facie evidence that he or she was under the influence of an intoxicant and is prima facie evidence that he or she had an alcohol concentration of 0.08 or more.