Every motor vehicle, trailer, semitrailer and pole trailer when driven or moved upon a highway shall be subject to this title with respect to registration, certificate of title and inspection except:
(1) Any such vehicle driven or moved upon a highway in conformance with this title relating to manufacturers, transporters, dealers or nonresidents or under a temporary registration permit issued by the Department as hereinafter authorized;
(2) Any vehicle used or intended to be used solely upon private property which must cross or use the public highway only incidentally in order to gain access from one portion of such property to another. This paragraph shall not apply to mobile homes or house trailers.
(3) Any vehicle owned by the government of the United States and plainly marked to indicate such ownership and identify the particular vehicle, unless said vehicle is under lease with a right of purchase in the lessee.