“Downtown primary street” means that portion of Oak Avenue which lies between Front Street and 13th Street, those portions of State Avenue and Columbia Avenue which lie between Front Street and Seventh Street and those portions of Front Street, First Street, Second Street, Third Street, Fourth Street, Fifth Street, Sixth Street and Seventh Street which lie between State Avenue and Columbia Avenue.

“Heights primary street” means that portion of 12th Street which lies between May Avenue and Belmont Avenue, that portion of 13th Street which lies between Oak Avenue and Belmont Avenue, that portion of May Avenue between 12th and 13th Streets and that portion of Belmont Avenue which lies between 12th Street and 13th Street.

“Snow condition” means that it is snowing within the city or that snow or ice has accumulated on a street in sufficient quantities to present a dangerous condition.

“Snow tires” means tires mounted on drive wheels of motor vehicles which are especially designed to give effective traction on snow, mud or ice covered streets by means of extra heavy duty treads with special high traction patterns, except that no tire so defined shall be construed to be a snow tire if it is damaged or worn to the extent that its performance would be substantially impaired.

“Street” of “Avenue” means any public road or highway within the city designed and ordinarily used for vehicular travel and parking.

“Tire chains” means any metal chains or cable mounted on drive wheel tires of motor vehicles which cross the tread of each such tire laterally in at least three different places.