a. The driver of a bus or taxi shall not park upon any street in any business district at any place other than at a bus stop or taxi zone, respectively, except that this provision shall not prevent the driver of any such vehicle from temporarily stopping in accordance with other stopping or parking regulations at any place for the purpose of and while actually engaged in loading or unloading passengers.

b. No person shall stop, stand or park a vehicle at any time in a place marked as a no parking zone by sign or red painted curb, except that a driver of a bus may stop to unload and load passengers in such a zone if signs indicate a bus loading zone.

c. No person shall stop, stand or park a vehicle other than a taxi in a place indicated by signs as a taxi standing zone. (Code 1962, § 37-50.21)