Access Nuclear Bus
Go to options menu, hold L1+R1 and press triangle, triangle, square, x

Unlock all leveles
Press up,up,down,up,up,up,down,down,up,down

Change date
- verify please ?
Change the date on your ps2 configuration to 25th december to unlock apu's xmas car !!! also works on 1st january for krusty!! and halloween but i forgot the date so you can work that one out, this unlocks barts frankinstien soap box racer !! iant i so clever!!!

To get smithers w/Burnse's car
Hold L1+ R1 Press Triangle Twice + Square Twice To Get Smithers Driving Burnse's Car (You Have To Be On Options)

Rocket Powered Car
Just outside Mr Burns mansion jump out of your car and run around until you get to the pink house and there will be a Rocket Powered Car. Jump in it and it's the fastest car on the game or you can by it but is the last thing you can get on the game. You will every race in it and get away from the Springfeild Cops if they try and chase you, but beware that if you crash it is easily destroyed so drive sensibly sometimes in it.