What is the test for a jury to find a driver not negligent per se for using her headlights?

It is evident from the record that the jury found for White on the issue of her use of headlights under Vehicle Code sections 24407 and 24409 because of a failure of proof. Barkus simply did not present any evidence on this issue. In this respect, McCallum v. Howe (1952) 110 Cal.App.2d 792 (McCallum) is instructive and applicable. In that case, the two plaintiffs were injured when the defendant driver hit them as they crossed a street (not at a crosswalk) while holding hands. It was dark at the time and the evidence showed the driver did not see the plaintiffs before striking them with his vehicle. The evidence further showed the vehicle's headlights were on low beam and shone only 15 feet instead of the 100 feet required by the Vehicle Code. The jury rendered a verdict for the driver. On appeal, the plaintiffs argued the driver was negligent per se for violation of the Vehicle Code. The appellate court disagreed: