California Supreme Court's recent DUI ruling is fair, just and realistic. "Partition ratio evidence" is again admissible in California drunk driving trials to defend and rebut the "impairment" DUI charge.
California has two separate charges for DUI - driving under the influence of alcohol and/or drugs (generic impairment DUI law) and driving with a blood alcohol level of .08% or more (per se DUI law).
California DUI attorney prosecutors usually charge folks with both impairment and per se violations.
A person accused of driving in California with a blood alcohol level of .08 or above may be found not guilty or guilty of violating the per se law. One cannot legally drive if eight hundredths of one per cent of one’s blood is alcohol.
The most common California DUI test for being under the influence determines the amount of alcohol in one’s breath. To determine if one is in violation of the law it is necessary to convert the amount of alcohol in one’s breath to the amount in the blood. By statute, in the per se law the conversion factor, known as the partition ratio is 2100:1 which means that the amount of alcohol in 2100 liters of breath is the same as in one liter of blood. But the partition ratio is different for different individuals and at different times for the same individual. Just the same, as far as the per se law is concerned, evidence that the defendant has a different partition ration or that 30 per cent of people, in general have a different partition ratio, is immaterial since by law you are in violation if you have a blood alcohol level of .08 or greater using a 2100:1 ratio.
Under the impairment or generic California DUI / driving under the influence law:
To be ‘under the influence’ within the meaning of the Vehicle Code, the liquor or liquor and drug(s) must have so far affected the nervous system, the brain, or muscles as to impair to an appreciable degree the ability to operate a vehicle in a manner like that of an ordinarily prudent and cautious person in full possession of his faculties.
The California Supreme Court previously had determined that evidence of an individual’s partition ratio is immaterial in a per se case because the law sets the ratio at 2100:1. However, under this new case of People v. McNeal, the court decided that since the presumption that you are under the influence uses a 2100:1 ratio, a defendant may use evidence of his/her unique ratio or of the inaccuracy of partition ratios in general to rebut the presumption that he/she is under the influence for purposes of generic or impairment DUI charges.
Mr. McNeal was charged with generic California DUI - driving under the influence law and violating the California .08 per se law. At trial, his purported breath / blood alcohol result was measured at .10% using a California DUI breath test.
After the evidence, his California DUI criminal defense lawyer requested permission to reopen the defense case with evidence regarding the partition ratio. There was no showing of whether he/she wanted to provide evidence in general or more specifically related to McNeal. The California DUI jury acquitted him on the per se violation but found him guilty on the California DUI generic or impairment allegation. The California DUI court denied permission. The California DUI criminal defense attorney's motion for a new California DUI trial was denied so the California DUI appeal followed.
The California Supreme Court held that California DUI evidence relating to partition ratio both as it specifically applied to McNeal and in general. The known scientific fact that 30% of all people have a partition ratio other than 2100:1 is admissible to counter evidence obtained by a breath test using a partition ratio of 2100:1.
A different partition ratio means that a person's reported California DUI breath test BAC may be falsely elevated based on the notion that the person may have a different partition ratio.