Cargo-carrying volume
Cargo-carrying volume means the luggage capacity or cargo volume index, as appropriate, and as those terms are defined in 40 CFR 600.31508, in the case of automobiles to which either of these terms apply. With respect to automobiles to which neither of these terms apply, cargo-carrying volume means the total volume in cubic feet, rounded to the nearest 0.1 cubic feet, of either an automobile's enclosed nonseating space that is intended primarily for carrying cargo and is not accessible from the passenger compartment, or the space intended primarily for carrying cargo bounded in the front by a vertical plane that is perpendicular to the longitudinal centerline of the automobile and passes through the rearmost point on the rearmost seat and elsewhere by the automobile's interior surfaces.