Partition Ratio Variability Evidence
is Relevant to and May be Used in a Generic DUI Charge,
but it May Not be Used to Rebut the
Same Presumption in a "Per Se" DUI Charge.
Veh.Code §23512(b) makes it a crime to
drive with a blood-alcohol content of 0.08 percent or more as measured in grams
of alcohol per 100 milliliters of blood or per 210 liters of breath. The crime
itself is defined in terms of a prohibited blood or breath result. People v.
McNeal, 46 Cal.4th at 1199. Veh.Code §23610 specifically
mandates that it "shall not be construed as limiting the introduction of any
other competent evidence bearing upon the question of whether the person
ingested any alcoholic beverage or was under the influence of an alcoholic
beverage at the time of the alleged offense." Id.
at (c). Thus, even in light of the presumption, a defendant charged under the
generic 23152(a) provision is entitled to offer "other competent evidence"
relevant to whether he was actually under the influence of alcohol. Id.
Competent evidence that the 2,100-to-1
ratio does not accurately reflect the partition ratio for all people, or that
the defendant's partition ratio may have been lower, is relevant to this
question. "Relevant evidence' means evidence ... having any tendency in
reason to prove or disprove any disputed fact that is of consequence to the
determination of the action." Evid.Code § 210. when a defendant's breath
test result is equivalent to 0.08 percent or more of blood alcohol, section
23610 permits the jury to infer he was indeed under the influence of alcohol.
The defendant is entitled to challenge this inference and can do so by, among
other things, raising a reasonable doubt as to whether the test result was an
accurate measure of his blood-alcohol level. Evidence casting doubt on the
accuracy of the breath-to-blood conversion ratio is just as relevant as other
evidence rebutting the presumption of intoxication from a breath test result,
such as evidence that the defendant had a high tolerance for alcohol or
performed well in field sobriety testing. People v. McNeal, 46 Cal.4th
at 1200.
Thus, evidence
about partition ratio variability is relevant in generic DUI cases to rebut the
presumption of intoxication in section 23610. However, this evidence
about partition ratio variability is irrelevant in those cases because the
Legislature incorporated a 2,100-to-1 partition ratio within its definition of
the offense. The result of the statutorily mandated test remains admissible,
and the jury is still properly instructed on the presumption. Defense evidence
is relevant to rebut the presumption that the defendant was intoxicated, but
not to remove the presumption altogether. People v. McNeal, 46
Cal.4th at 1200-1201.
The information on this California Criminal Defense Attorneys / Law Firm website is for general information purposes only. Nothing on this or associated pages, documents, comments, answers, emails, or other communications should be taken as legal advice for any individual case or situation. This information on this website is not intended to create, and receipt or viewing of this information does not constitute, an attorney-client relationship.
