Idaho has adopted 390.21 of the Federal Motor Carrier Safety Regulations, as published and annually recompiled.
Section 390.21 applies to intrastate carriers operating commercial motor vehicles transporting property with a gross vehicle weight, gross vehicle weight rating, gross combination weight, or gross combination weight rating greater than 26,000 pounds, and intrastate carriers transporting placardable quantities of hazardous material subject to the authority of the Idaho State Police.