What is the burden of proof under a negligence cause of action?

To succeed at trial under a negligence cause of action plaintiff must establish by a preponderance of the evidence the truth of those allegations in his complaint which are placed in issue (Polk v. Polk (1964)228 Cal.App.2d 763, 787, 39 Cal.Rptr. 824). It is clear that plaintiff's burden of proof that defendants were negligent in the present case was not coextensive with the showing required by plaintiff in seeking imposition of sanctions for denial of specific facts by defendants on pretrial requests for admissions. It is mandatory that the court impose sanctions against either party when the other party makes application showing that (a) any fact of substantial importance was denied by his opponent and (b) such denial was without good cause. (Code Civ.Proc., [87 Cal.App.3d 275] 2034, subd. (c).) One need not be a prevailing party to be entitled to sanctions under this statute.