Multiplayer in The Simpsons: Hit & Run? None—Single-Player Only

You cannot access bonus or unlockable multiplayer action in The Simpsons: Hit & Run. This game is a single-player adventure with no built-in multiplayer feature.

The multiplayer aspect you may be thinking of likely comes from other games in the franchise, such as The Simpsons: Tapped Out, a mobile game with social features allowing you to visit friends' towns and send gifts.

If you're looking for multiplayer fun, consider other games in The Simpsons universe, or simply pass the controller with a friend for a shared single-player experience!