Proving grounds track:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold R1 and press Left, Circle, Up, Down, Right, Right, Right when the credits begin to roll.

Treasure Island track:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold L2 and press Square, Circle, Square, Up, Up, Down, Up, Left, Right, X when the credits begin to roll. Or, win a season under the veteran difficulty setting.

Asher Boldt car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold L2 and press Square, Circle, Triangle, X when the credits begin to roll.

Jocko Michaels car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold L1 and press Square, Triangle, Square, Circle, Square, X when the credits begin to roll.

John Andretti's second car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold R1 and press Square, Triangle, Square, Triangle when the credits begin to roll.

KC Monoxide car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold L2 and press Square, Circle, X, Down, Up, Right, Left when the credits begin to roll.

Shorty Leung car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold R2 and press Square, Circle, X, Up, Down, Left, Right when the credits begin to roll.

4th From The Sun car:
Choose "Credits", then "Development" at the options menu. Wait for the FMV sequence to complete, then hold L1 then press Up, Square, Left, Circle, X, Square, Triangle, Right when the credits begin to roll.

Black Box Classic car:
Win the Short Track Challenge to get the Black Box Classic car.

Black Box Exotic car:
Win the Half Season to get the Black Box Exotic car.

EA Sports car:
Win the Road Course Challenge to get the EA Sports car.

EA.com car:
Win the Superspeedway Shootout on either veteran or legend difficulty settings.

Richard Petty car:
Win a season on the rookie difficulty setting.