When you are on the highway in Arcade mode you can flip vehicles over by driving on the high lane and then knocking a truck that says 'wow' off of it onto the low lane so it crashes into a truck or bus.
When you complete ALL the Crazy Box games with a character you will be able to access the bike by pressing 'Up' when you select a driver in Original mode or Arcade mode. Customers will pay more to be taken by bike.
When you complete the 9 original mini-games 6 more new ones will become unlocked in the process. When you then cmplete the final new mini-game you will be able to select a bike for any of the characters by pressing 'Up' or 'Down' at the 'Character' selection screen.