Leo claims in the examples that I could "get off a car" meaning "getting out of a car".
Yesterday, an English friend told me that I can only "get out of a car" but I cannot "get off a car".
Yes, I think that entry should be changed. If 'car ' is meant in its normal sense in British English, i.e. an automobile, then 'get off a car' is wrong. If it's meant in any other way, this should be made clear -- but then why not just use, for instance, 'bicycle' instead.
He explained that "I can safely get off anything I can ride" but I cannot ride a car.
I find this explanation strange. True, you don't ride a car, but then you don't (at least in Britain) ride a train either. (You can go for a train ride or for a ride on a train, but equally you can go for a car ride / a ride in a car, so there's no distinction there.)
I imagine the point is simply that you are on the train and you get off, whereas you're in the car and you get out.