49 CFR 244.3 - Preemptive effect.
Under 49 U.S.C. 20106, issuance of these regulations preempts any State law, regulation, or order covering the same subject matter, except an additional or more stringent law, regulation, or order that:
(a) Is necessary to eliminate or reduce an essentially local safety hazard;
(b) Is not incompatible with a law, regulation, or order of the United States Government; and
(c) Does not unreasonably burden interstate commerce.