Complete each tier of tracks in arcade mode on any difficulty setting to unlock the next tier of tracks:

Tier 1
Super Speedway, Midfield Raceway, Smokey Mountain, Swiss Alps, Trial Mountain, Midfield Raceway II.

Tier 2
Smokey Mountain II, Tokyo R246, Grand Valley Speedway, Laguna Seca Raceway, Rome Circuit, Tahiti Circuit.

Tier 3
Swiss Alps II, Trial Mountain II, Deep Forest Raceway II, Special Stage Route 5, Seattle Circuit, Test Course.