I told my better half that she should say she's "getting on the bus" rather than "getting in the bus." She asked me why, because you would "get in the car" and not "get on the car." (You could get on a car, but we'd be talking about riding on the roof.)
I couldn't answer why, but I came up with a quick rule, which so far hasn't been proven wrong:
If you can stand up/walk around inside the vehicle, you use on: bus, plane, boat.
If you can't stand up/walk around, you use in: car ... what else, go-kart? Haha.
In my mind, when I try to analyse it myself, you are getting inside the bus, you're not getting on top of it. So why "on"?
Does anybody know why this is/can tell me reasons for this?
P.S. is my rule wrong? I thought of motorcycles/bicycles, but I figure different rules apply for modes of transportation that don't have "cabins."
Just some extra info:
My linguist friend sent me a link to a pretty cool talk back radio show about the English language called "A Way With Words" -- somebody had recently asked about in a car vs. on a train: http://www.waywordradio.org/in-a-car-on-a-train/
Their consensus is the same as mine (they called it "freedom of movement, or embedded as a unit" [consider the freedom of movement on a train, lol not at rush hour I guess, vs. embedded as a unit like being in a canoe]) however, what @Jonah mentioned about private vs. public buses really does make a lot of sense.
P.P.S I would recommend subscribing to A Way With Words if you are learning English, a lover of English, or just want to learn more about it! I've listened to one episode so far and it's quite interesting, not as dry as I imagined a radio show like that would be. About the hosts: Martha is an author, and Grant is a lexicographer and dictionary editor.