Motor Mash is a multiplayer mode in which the goal is to damage your opponents' cars as much as possible. You earn points whenever you damage an opponent's car, and the person with the most points at the end of the time limit is the winner.
Each person is assigned a rival for the match. Damaging your rival will earn you extra points. If you are wrecked, your rival will be reassigned to the person that wrecked you car.
There are four tracks for Motor Mash:
- Dust Bowl in Amboy: a large circular bowl with a flat track around the edge
- La Carretera in Barcelona: a long oval arena with raised areas on the 2 ends and a hill in the middle
- Figure of 8 in LA Downtown: a looping figure-8 track with some ramps near the crossing point
- LA Heights in LA Downtown: 2 floors of a high-rise builiding without completed walls and an adjoining building rooftop accessable via a ramp
This mode is available in online play and local area network (LAN) play. In online play, this mode is not available at the beginning of the game. It must be unlocked by gaining levels through the fan system.