What is the burden of proving beyond a reasonable doubt in a motor vehicle accident case?

weight, of alcohol in [his] blood. "³ ( Burg v. Municipal Court (1983) 35 Cal.3d 257, 265, 198 Cal.Rptr. 145, 673 P.2d 732 ( Burg ).) "[T]he People still must prove beyond a reasonable doubt that at the time he was driving his blood alcohol exceeded 0.10 percent." (Ibid. )

"The effect of a presumption affecting the burden of producing evidence is to require the trier of fact to assume the existence of the presumed fact unless and until evidence is introduced which would support a finding of its nonexistence, in which case the trier of fact shall determine the existence or nonexistence of the presumed fact from the evidence and without regard to the presumption." ( Evid.Code, 604.) In other words, when met with "contradictory evidence," the presumption "disappears." ( Craig v. Brown & Root, Inc. (2000) 84 Cal.App.4th 416, 421, 100 Cal.Rptr.2d 818.)