Preposition for Transport - Set 2

When do we use 'in' and 'on' for different forms of transportation? Why is it 'on the bus' and 'in the car'?  What is the difference?  Well, let's take a short look: on the bus, on the train, on the ship, on the plane - These are all forms of public transportation. in the car, in the boat, in the canoe - These are forms of private transportation. It appears that 'on' is used with public forms of transportation whereas 'in' is used with private forms of transportation.  But, becareful there are some exceptions to this rule.  We have things that we 'ride on'.  For example, on a bike, on a horse, on an elephant, etc...  We also have at least one form of semi-private transportation, in a taxi.  I guess taxis are cars so we say 'in a taxi'. Let's review! Let's say I need to catch a plane in Tokyo, but I live in Osaka.  So, I rode on my bicycle to get to my friends house.  He drove me, so I rode in a car to get to Osaka station.  Then, I rode on a train to Tokyo.  Finally, I rode in a taxi to Narita airport.  (I was in a hurry.)