A.
Any truck having a total combined gross weight of vehicle plus load in excess of five tons shall be excluded from all streets in the City, except from those streets or parts of streets hereinafter listed or described which form a part of the system of truck routes upon which trucks are permitted to travel and operate.
B.
The total combined gross weight of vehicle plus load shall be ascertained by computing the entire weight of the truck or vehicle plus load or, in the event that such vehicle is a tractor-trailer combination, then by computing the entire weight of a tractor and trailer plus load.
C.
Such exclusions shall not prevent the necessary delivery of merchandise or other property along the streets from which trucks are excluded, provided that the vehicle from which any such delivery is made shall enter and leave any such designated truck route by the nearest accessible street to the place where such delivery is made, and provided that such delivery vehicles shall remain on such prohibited streets for a period of time no longer than necessary and reasonable to make such delivery or to complete a loading of such vehicle; nor shall such exclusions prevent the necessary operation of trucks while in use by the United States Postal Service or military services or by fire, police, sanitation or street maintenance services, or by public transportation corporations on franchised routes or by public service corporations while on emergency repair work.