Sudden braking is permitted when:

1. Correct answer: It is the only way to prevent an accident.
2. The driver or any of the passengers suddenly want to get off the vehicle.
3. The driver wants to make a U-turn.
4. The driver realizes he is lost.

WhySudden braking is only for when it is the only way to prevent an accident. If you missed your turn or want to get out, brake gently.