## Facts

- The Williamson family rode in a 1993 Mazda MPV minivan; a rear inner “aisle” seat was equipped with a lap-only belt, while other occupied seats had lap-and-shoulder belts.
- A head-on collision occurred with another vehicle combination; the rear aisle-seat passenger, wearing the lap-only belt, suffered fatal internal injuries, while other occupants survived.
- At the time, FMVSS 208 required lap-and-shoulder belts for certain rear outboard seats but permitted manufacturers to choose either lap-only or lap-and-shoulder belts for certain rear inner seats, including the aisle seat.
- The Williamsons sued Mazda under California tort law (including strict liability and negligence), alleging Mazda should have installed a lap-and-shoulder belt in the rear inner aisle seat.
- California courts dismissed/affirmed on preemption grounds, reasoning that the federal regulation’s permitted option barred the state claims; the Supreme Court granted review.

## Issues

1. Whether FMVSS 208’s permitted choice between lap-only and lap-and-shoulder belts for certain rear inner seats conflict-preempts a state tort claim alleging the manufacturer should have installed lap-and-shoulder belts.

## Decision

- The Supreme Court unanimously reversed and remanded.
- The Court held that FMVSS 208 did not preempt the state tort claims challenging the use of a lap-only belt in the rear inner seat.
- The Court distinguished prior precedent finding preemption where a federal safety standard intentionally sought a manufacturer “mix” of restraint options as a central regulatory objective.

## Legal Principles

- The Motor Vehicle Safety Act’s express preemption clause does not itself bar common-law tort suits, and the saving clause does not eliminate ordinary conflict-preemption analysis.
- Conflict (obstacle) preemption applies only when a state rule would frustrate significant federal regulatory objectives.
- A regulatory option does not automatically imply a federal objective to preserve manufacturer choice; courts must examine regulatory history and agency aims to determine whether maintaining the option was an important federal goal.
- Where a federal standard sets a minimum requirement and the option exists mainly due to cost/feasibility considerations rather than a policy favoring variety, state tort duties may coexist without creating an obstacle.

## Conclusion

Because the federal decision to permit lap-only belts for certain rear inner seats was not shown to embody a significant federal objective to preserve manufacturer choice, the California tort claims seeking lap-and-shoulder belts did not conflict with FMVSS 208 and were not preempted.


Williamson v. Mazda Motor of Am., Inc., 131 S. Ct. 1131 (2011)