A condition is not a dangerous condition within the meaning of this chapter if the trial or appellate court, viewing the evidence most favorably to the plaintiff, determines as a matter of law that the risk created by the condition was of such a minor, trivial or insignificant nature in view of the surrounding circumstances that no reasonable person would conclude that the condition created a substantial risk of injury when such property or adjacent property was used with due care in a manner in which it was reasonably foreseeable that it would be used.
Ca. Gov. Code § 830.2