NHTSA is revising the federal standard for vehicle roof strength under the Motor Vehicle Safety Act. With regard to preemption, here is what NHTSA claims compared to the language of the act.

Preemption of state positive law

NHTSA's view:
"…section 30103(b) of 49 U.S.C. provides, 'When a motor vehicle safety standard is in effect under this chapter, a State or a political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter.' Thus, all differing state statutes and regulations would be preempted." 70 FR 49245

Motor Vehicle Safety Act:
"Preemption.—(1) When a motor vehicle safety standard is in effect under this chapter, a State or a political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. However, the United States Government, a State, or a political subdivision of a State may prescribe a standard for a motor vehicle or motor vehicle equipment obtained for its own use that imposes a higher performance requirement than that required by the otherwise applicable standard under this chapter." 49 U.S.C. 30103(b)

Preemption of tort law

NHTSA's view:
"…if the proposal were adopted as a final rule, it would preempt all conflicting State common law requirements, including rules of tort law." 70 FR 49246

Motor Vehicle Safety Act:
"Common Law Liability.—Compliance with a motor vehicle safety standard prescribed under this chapter does not exempt a person from liability at common law." 49 U.S.C. 30103(e)