(A) It is unlawful to park a detached semi-trailer upon any street, city-owned parking lot or other public property.
(B) It is unlawful to park a truck (other than a truck of 12,000 pounds gross vehicle weight or less), truck trailer, tractor-trailer or truck-tractor within an area zoned as a residential district, or within 300 feet thereof, except for the purpose of loading or unloading the same, and then only during such time as is reasonably necessary for the activity, but not between the hours of 6:00 p.m. and 6:00 a.m. of the day next following.
(C) It is unlawful to park a commercial vehicle of more than 12,000 pounds gross vehicle weight upon any street in the business district, except streets as specifically designated by the Council by resolution and sign-posted, but parking of the vehicle for a period of not more than 20 minutes shall be permitted in the space for the purpose of necessary access to abutting property while actively loading or unloading when the access cannot reasonably be secured from an alley or from an adjacent street where truck parking is not so restricted.
(D) It is unlawful to park a truck or other vehicle using or equipped with a trailer, or extended body or other extension or projection beyond the original length of the vehicle, or any passenger bus, diagonally along any street, except for a time sufficient to load or unload and, in such case, only parallel parking shall be permitted; provided, however, that, a truck may stand backed up to the curb if the weight or bulk of the load makes parallel parking impracticable, but then only for a period of time sufficient to load or unload.
(E) Parking of commercial vehicles is permitted in duly designated and signposted loading zones, and in alleys, for a period of up to 20 minutes; provided that, the alley parking does not prevent the flow of traffic therein, all of which shall be for the purpose of access to abutting or adjacent property while actively loading or unloading.