Why was the translation of On attend le bus, We wait for the bus and not One waits for the bus?

Hi Olivia,

the French "on" is very commonly used to mean "we" in spoken French. So much so that it is often more frequently used than the proper "nous", particularly in colloquial French. 

In the sentence you quote, one would, strictly speaking, need more context to make a definitive decision. 

-- Chris (not a native speaker).