Williamson v. Mazda Motor of America

Thanh Williamson died when her family’s minivan was struck head-on by another vehicle. Thanh was sitting in the rear aisle seat, wearing only a lap belt. The other members of the Williamson family (plaintiffs) were wearing lap-and-shoulder belts, and they survived. The Williamsons brought an action in California state court against Mazda Motor of America (Mazda) (defendant) on behalf of themselves and Thanh’s estate. Federal Motor Vehicle Safety Standard 208 (the federal seat belt regulation), issued by the Department of Transportation (DOT), required manufacturers to install lap-and-shoulder belts in seats adjacent to the door or frame of a vehicle. The federal seat belt regulation permitted manufacturers to decide whether to install lap belts or lap-and-shoulder belts in other seats, such as middle seats. The Williamsons alleged that, under state tort law, Mazda should have installed safer lap-and-shoulder belts in its rear aisle seat. Mazda argued that the preemption clause of the United States Constitution required a finding that the federal seat belt regulation, in allowing manufacturers to choose which sort of seat belts to provide in middle seats, preempted state tort claims that might eliminate manufacturer choice. The trial court dismissed the tort claim. The state appellate court affirmed the trial court’s decision. The Williamsons appealed to the United States Supreme Court.