There are five licenses available in Gran Turismo 4. Acquisition of each license is progressively more difficult to achieve than the last. Each license enables the player to enter more difficult events in career mode. Driving Missions become available when the iB license is passed, with later missions unlocked at iA level.
The Licenses are (in increasing level of difficulty):
Each license consists of sixteen driving tests and a Coffee Break. Performance for each test is graded to one of four levels: gold, silver, bronze or fail. All 16 tests must be completed to at least a bronze level to acquire the license and a prize car. Coffee Breaks are non-compulsory.
Subsequent prize cars are awarded when all tests are passed to silver and gold levels.