What is the test for determining whether a defendant's actions were a proximate or legal cause of death in a motor vehicle accident?

Tort principles of proximate or legal causation apply to crimes; thus, the defendant's acts must be the legally responsible cause of the injury, death, or other harm constituting the crime. (People v. Schmies (1996) 44 Cal.App.4th 38, 46-47.) "To be considered the proximate cause of the victim's death, the defendant's act must have been a substantial factor contributing to the result, rather than insignificant or merely theoretical. [Citations.]" (People v. Briscoe (2001) 92 Cal.App.4th 568, 583-584, fn. omitted.) "[A]s long as the jury finds that without the criminal act the death would not have occurred when it did, it need not determine which of the concurrent causes was the principal or primary cause of death." (People v. Catlin (2001) 26 Cal.4th 81, 155.)

Page 12