Every vehicle, at all times while being driven, stopped or parked upon the streets or alleys of the city, shall be registered in the name of the owner thereof in accordance with the laws of the state, unless such vehicle is not required by the laws of the state to be registered in this state, and shall display in proper position valid and unexpired registration plates or indicia of registration meeting the requirements of the laws of the state, clear and distinct and free from defacement, mutilation, grease and other obscuring matter, so as to be plainly visible and legible at all times; provided, however, if such vehicle is not required to be registered in this state, the indicia of registration issued by another state, territory, possession or district of the United States or a foreign country, substantially complying with the provisions of this chapter, shall be considered as compliance with this title. (Prior code § 42-15-36)