49 CFR § 397.61
Purpose and scope
November 18, 2020
This subpart contains routing requirements and procedures that States and Indian tribes are required to follow if they establish, maintain, or enforce routing designations over which a non-radioactive hazardous material (NRHM) in a quantity which requires placarding may or may not be transported by a motor vehicle. It also provides regulations for motor carriers transporting placarded or marked NRHM and procedures for dispute resolutions regarding NRHM routing designations.