Begin with extra money 
     At  the  title  screen,  press  L2,  SQUARE,  R1, CIRCLE, R1, L1,
CIRCLE, L2, SQUARE, R2, SQUARE, R1

Slow motion mode
     At the title screen press L1, L2, R1, R2, SQUARE, CIRCLE

Warp speed mode
     At the title screen, press L1, L2, R1, R2, SQUARE, SQUARE

Unlock all 18 trucks
     At the title screen, press L1, L2, R1, R2, L1, R1

Slower game speed
     During gameplay, pause the game and press L1, L2, R1, R2, SQAURE,
CIRCLE

Normal game speed
     During gameplay, pause the game and press L1, L2, R1, R2, CIRCLE,
CIRCLE

$25,000
     During gameplay, pause the game and press L2, SQUARE, R1, SQUARE,
R1, L1, CIRCLE, L2, SQUARE, R2, SQUARE, R1