(1) Operation on street of destination. The operation of trucks upon any street where necessary to the conduct of business at a destination point, provided streets upon which such traffic is permitted are used until reaching the intersection nearest the destination point.

(2) Emergency vehicles. The operation of emergency vehicles upon any street in the city.

(3) Public utilities. The operation of trucks owned or operated by the city, public utilities, any contractor or materialman while engaged in the repair, maintenance or construction of streets, street improvements or street utilities within the city.

(4) Detoured trucks. The operation of trucks upon any officially established detour if such truck could lawfully be operated upon the street for which such detour is established.