Nothing in this section shall preclude the city from allowing, under special and unusual circumstances, the temporary placement of any commercial coach, mobile/manufactured home or recreational vehicle on any street, alley, or other public right-of-way or public property, private lot or tract of ground when such placement will not in the opinion of the city create a health hazard or nuisance; nor shall it preclude any commercial coach, mobile/manufactured home or recreational vehicle from an approved sales lot, public storage, approved for such storage, or any zoning district, allowing same.