Driving on streets during excavations. No person shall go upon or drive, or cause to be driven, any vehicle on any street, alley or other public place which is excavated or in the process of being excavated for the purpose of constructing sewers, water mains, pavements, sidewalks or other public improvements, or which is newly paved, or upon which any public improvement of any nature is under construction, if such street, alley or public place is barricaded by authority of the City; provided that, where only a portion of a street is barricaded, any person who resides or keeps a business establishment upon said street, and has no other means of access to his residence or place of business, may go upon or drive a vehicle upon the unbarricaded portion of said street at his own risk, in order to reach said residence or place of business by the shortest practicable route, but only if the same may be done without injury to or interference with the improvement under construction.