As used in this title:

    "License plate" means any license plate, tag or decal approved by the city council and issued by the city clerk for the use of such motor vehicle or motor bicycle, as herein provided.

    "Motor vehicle" includes automobiles and all other vehicles propelled otherwise than by muscular power, except traction engines and road rollers, diesel railroad engines, and other motor vehicles running only upon rails or tracks, but nothing in this title shall be construed to apply to or affect bicycles or tricycles or such other vehicles as are propelled exclusively by human muscular power. (Prior code § 24-6-15)