How do you play arcade mode during a manager mode in Gran Turismo 4?

In Gran Turismo 4, you can access Arcade Mode from the main menu, but to play it during Manager Mode, you need to return to the main menu first. Once you're in the Arcade Mode, you can choose various race options and vehicles without affecting your Manager Mode progress. After you're done, you can simply reload your Manager Mode to continue your career. This allows for a fun break while still advancing in your primary game mode.