(see also this question on meta)
I noticed that this question was put on hold because "This question may invite speculative answers, as the question is not fully defined. The validity of some answers may be based upon opinion."
It is true that the puzzle, as it was stated, does not have a definite answer: an American and a Briton would give a different answer. But I think that the site would benefit if the statement was changed to avoid this ambiguity: and anyway other answers which based on lateral thinking - for example, "if the bus was running in reverse gear, then its direction would be..." are also useful.
What do you think?