Cargo-carrying unit.
Cargo-carrying unit. As used in this part, cargo-carrying unit means any portion of a commercial motor vehicle (CMV) combination (other than a truck tractor) used for the carrying of cargo, including a trailer, semitrailer, or the cargo-carrying section of a single-unit truck. The length of the cargo carrying units of a CMV with two or more such units is measured from the front of the first unit to the rear of the last [including the hitch between the units].