The City Administrator may, upon application and good cause being shown therefor, issue a special permit in writing authorizing the applicant to operate or move a vehicle or combination of vehicles of a size or weight or load exceeding the maximum specified by State law or the City over those streets or bridges named in the permit which are under the jurisdiction of the City and for which the City is responsible for maintenance.
(Code of Iowa, Sec. 321.473 & 321E.1)