First go to a Stunt Arena, then you must enable the high speed code, then do some tricks or powerslide twice, then you will now have boost, then, you will go so high, you will get out of the Stunt Arena, then you can get yourself large amounts of how many miles (or whatever the road sign means) and you can do so many amounts of how many times you did a trick, have fun! Note: To exit, wait till the time ran out or restart the Stunt Arena or return to the park, it's just a glitch, you will keep falling, you won't land it.