A Trial Court has Discretion to Deny a Defendant's Dilatory Motion to

Reopen in Order to Present Evidence on the Issue of the Variability of the Partition

Ratio Between the Concentration of Alcohol in the Blood and in Breath, 

      As a general matter, the “[a]pplication of the ordinary rules of evidence ... does not impermissibly infringe on a defendant's right to present a defense.” People v. Fudge (1994) 7 Cal.4th 1075, 1102-1103.   The Defendant in the case at bar attempted to enter the partition ratio variability after both sides had rested their case via a motion to reopen.  Like all other evidence, partition ratio evidence must be timely offered. The motion to reopen was one addressed to the court's sound discretion.  Id. at 1202-1203, citing to People v. Jones (2003) 30 Cal.4th 1084, 1110,   In the case at bar, the Defendant was not entitled to a reversal because any error in excluding the partition ratio evidence was harmless. People v. McNeal, 46 Cal.4^th at 1202-1203. 

      In the case at bar, even without partition ratio evidence, nearly half the jury rejected the accuracy of defendant's breath test result and declined to find that he had exceeded the legal limit of 0.08 percent blood alcohol. Nevertheless, all jurors believed defendant was “under the influence” for purposes of Veh.Code §23152(a).  The jury's verdict indicates that the admission of partition ratio evidence was not reasonably likely to have produced a more favorable result. Thus it was harmless error, not reversible error. People v. McNeal, 46 Cal.4^th at 1203. 
 

Case Disposition 

      Affirmed. The Court of Appeal’s ruling that while the Defendant could have presented evidence of the variability of the partition ratio between the concentration of alcohol in the blood and in breath to negate the presumption that they have been driving under the influence pursuant to Veh.Code § 23610 (a)(3), any error in excluding the partition ratio evidence was harmless.  
 

Application of Rule of Law 

      A defendant to a generic DUI charge may use the variability of the partition ratio between the concentration of alcohol in the blood and in breath to negate the presumption that they have been driving under the influence pursuant to Veh.Code § 23610 (a)(3). It may not be used to challenge a per se DUI charge.   

      The trial court has discretion to exclude dilatory presentations of evidence of partition ratio variation just like any other type of evidence. 
 

Implications 

      Challenging a “Per Se” DUI charge may not involve the rebuttal of the presumption of being under the influence pursuant to Veh.Code § 23610 (a)(3) with partition ratio variability evidence, but should be challenged in Generic DUI cases if it is helpful to the defense of the case.

      The evidence of the variability of the partition ratio between the concentration of alcohol in the blood and in breath is best brought forward at the earliest possible time as the trial judge has discretion to deny the entry of this evidence as being dilatory.