When approaching the crest of a grade or upon a curve in the highway where the driver's view is obstructed within such distance as to create a hazard in the event another vehicle might approach from the opposite direction.' In Yeager v. Bray, 138 Cal.App. 328, 32 P.2d 396, after setting forth certain calculations of speed and time, it was held that the evidence produced showed a violation of these sections and unerringly pointed to negligence causing or contributing to the injury. Plaintiffs rely principally upon the decision in Pohler v. Humboldt Motor Stages, Inc., 100 Cal.App.2d 571, 224 P.2d 440, 442, in support of the finding and judgment.