到底是on the car 還是in the car?

http://tw.blog.voicetube.com/2015/01/15/%E5%88%B0%E5%BA%95%E6%98%AFon-bus-%E9%82%84%E6%98%AF-bus%EF%BC%9F%E4%B8%80%E6%AC%A1%E6%90%9E%E6%87%82%E4%BA%A4%E9%80%9A%E5%B7%A5%E5%85%B7%E4%BB%8B%E4%BF%82%E8%A9%9E%EF%BC%81