It shall hereafter be unlawful for any person or person to move or operate heavy equipment across any curb, gutter, bridge, culvert, sidewalk, crosswalk, or crossing on any unpaved street without first having protected such curb, gutter, bridge, culvert, sidewalks, crosswalk, or crossing with heavy plank sufficient in strength to warrant against the breaking or damaging of such curb, gutter, bridge, culvert, sidewalk, crosswalk, or crossing. Hereafter, it shall be unlawful to run, drive, move, operate, or convey over or across any paved street a vehicle, machine, or implement with sharp discs or sharp wheels that bear upon said pavement; with wheels having cutting edges; with wheels having lugs, any protruding parts, or bolts thereon that extend beyond a plain tire so as to cut, mark, mar, indent, or otherwise injure or damage any pavement, gutter, or curb; provided, where heavy vehicles, structures, and machines move along paved or unpaved streets the Maintenance Superintendent is hereby authorized and empowered to choose the route over which the moving of such vehicles, structures, or machines will be permitted and allowed. Nothing in this section shall be construed to apply to pneumatic tires with metal or metal-type studs not exceeding five-sixteenths (5/16) of an inch in diameter inclusive of the stud-casting with an average protrusion beyond the tread surface of not more than seven sixty-fourths (7/64) of an inch between October 1, and April 15; provided, that school buses and emergency vehicles shall be permitted to use metal or metal-type studs all year; it shall be permissible to use farm machinery with tires having protuberances which will not injure the streets; and it shall be permissible to use tire chains of reasonable proportions upon any vehicle when required for safety because of snow, ice, or other condition tending to cause a vehicle to slide, or skid. (Ref. 39-6,131 RS Neb.)