What is the burden of proof of contributory negligence in a motor vehicle accident?

The court pointed out that the burden of proof of contributory negligence rests upon the defendant and that in order to justify the submission of that issue to the jury there must be a fact or facts from which a reasonable inference of contributory negligence can be drawn, based upon substantial evidence and not upon conjecture, surmise or guess-work, and, quoting from Bardin v. Case (1950) 99 Cal.App.2d 137, 142, 221 P.2d 292, 295, the proof "* * * must be such that a rational, well-constructed mind can reasonably draw from it the conclusion that the fact exists; and, when the evidence is not sufficient to draw such inference, the court should refuse to submit the question to the jury."

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