"El hombre es conductor de autobús."
It's saying the man is a driver of a bus. Your's is too specific.
But how can you tell that this he is "a" bus driver and not "the" bus driver given that neither is specified in the Spanish?
In Spanish, Conductor is Driver, but in English the Conductor was the man that took the money and gave the tickets, but they do not have them anymore and the driver has to do it all on his own They call it Progress, like save on wages HA!