What is the test for a special verdict in a motor vehicle accident?

We disagree with appellant's interpretation of the special verdict. David v. Hernandez (2014) 226 Cal.App.4th 578 (David) is instructive. In David, appellants brought a negligence action against a truck driver after their car collided with his tractor-trailer. (Id. at p. 581.) The jury returned a special verdict finding that the truck driver was negligent, "but that his negligence was not a substantial factor in causing harm to appellants." (Id. at p. 585.) Appellants asserted on appeal that the verdict was "fatally inconsistent because 'a finding of causation flows automatically from the negligence finding.' " (Ibid.)