What is the test for an appellate court to overturn a verdict in a motor vehicle accident case?

As recognized in Uva v. Evans (1978) 83 Cal.App.3d 356, 147 Cal.Rptr. 795: "The power of an appellate court to review the trier of fact's determination of damages is severely circumscribed. An appellate court may interfere with that determination only where the sum awarded is so disproportionate to the evidence as to suggest that the verdict was the result of passion, prejudice or corruption ... or where the award is so out of proportion to the evidence that it shocks the conscience of the appellate court. [Citations.]" (Id. at pp. 363-364, 147 Cal.Rptr. 795.)