18 Wheeler: American Pro Trucker Cheats

On level 4 drive to the town go through it until you get to the small bridge before the dirt road go around the corner fast and hit the inside of the turn before the guard rail and you should jump the games boarder you will see nothing but trees and glimpses at the road

Finish arcade mode with all 4 original drivers to unlock a new
character and truck.

Successfully complete each of the four parking levels to unlock an additional parking level. Successfully complete the bonus parking level to unlock a sixth parking level.

This game is quite lame it should be taken off of the gamecube game list.
Press r right when the turns green and you will go faster
Aphsalt cowboy is the best...

Successfully complete arcade mode with all four characters

If you complete Arcade Mode on any difficulty with all four original truckers, not only do you get the new trailers for Score Attack Mode, but you also get them in Versus Mode. You can also use them in Arcade Mode if you select the Nippon Maru truck.