What is the test for determining whether a violation of a statutory requirement is justified or justifiable?

'In the application of this rule each violation of a statutory requirement must be considered in connection with the surrounding circumstances. Ordinarily, the excuse relied upon by the violator presents a question of fact for the jury's determination. As stated in Scalf v. Eicher, supra, 11 Cal.App.2d at page 54, 53 P.2d at page 373: 'Whether or not a violation of a statute or ordinance proximately contributed to an accident and whether the violation was excusable or justifiable are questions of fact except in a case where '* * * the court is impelled to say that from the facts reasonable men can draw but one inference, and that an inference pointing unerringly to the negligence of the plaintiff contributing to his injury.'' (Citing cases.)'

The court also instructed as to the life expectancy of the plaintiff, but omitted the qualifying conditions about normal health. As said in Newman v. Campbell, 23 Cal.App.2d 639, at page 641, 73 P.2d 1265, at page 1266: