49 CFR § 172.701
Federal-State relationship
November 18, 2020
This subpart and the parts referenced in §172.700(c) prescribe minimum training requirements for the transportation of hazardous materials. For motor vehicle drivers, however, a State may impose more stringent training requirements only if those requirements—
(a) Do not conflict with the training requirements in this subpart and in part 177 of this subchapter; and
(b) Apply only to drivers domiciled in that State.