(a) Vehicles—every device in, upon or by which any person or property is or may be transported or drawn upon a public road or highway, excepting devices moved by human power or used exclusively upon stationary rails or tracks.
(b) Commissioner—the term “Commissioner” shall include the Commissioner of Public Works or any employee of the Department of Public Works designated in writing by the Commissioner of Public Works.
(c) Owner—the term “owner” means any person, firm, corporation or association holding title to a motor vehicle, or having the legal right to register the same, including purchases under conditional bills of sale, or renting a motor vehicle or having the exclusive use thereof under a contract or lease or otherwise.
(d) Solid tires—the term “solid tires” means tires of rubber, or other elastic material, which do not depend upon confined air for the support of the load.
(e) Person—the term “person” includes any individual, corporation, association, partnership, firm or other aggregation of individuals.
(f) Pneumatic tires—the term “pneumatic tires” means tires inflated or capable of inflation with air.