(a) For the purposes of this subchapter, the United States parcel post shall be deemed a carrier, and the provisions of this subchapter relating to transportation by carrier shall apply, so far as they may be applicable, to transportation by parcel post.

(b) For the purposes of this subchapter, the operator of every ferry shall be deemed a carrier, and the provisions of this subchapter relating to transportation by carrier shall apply to transportation by ferry of any products loaded on a truck or other vehicle, or otherwise moved by such ferry.