Bert Marolla (plaintiff) was working for a railroad company when he was operating an electric train car across a track intersection. Wayne Hetzer was driving an electric car perpendicular to Marolla’s car. Both cars approached the intersection, and they collided. The customary railroad rule called for drivers to approach intersections with complete control and to stop if necessary. Marolla brought suit against Hetzer’s insurance company, American Family Mutual Insurance Company (defendant). During the trial, the court barred evidence of the custom of Marolla’s employer regarding operating trains at track intersections, and the jury found Hetzer was 75 percent negligent and Marolla was 25 percent negligent. The insurance company appealed.