If you consider the rules for human defensive driving as gospel, the safety side of this problem seems to go away. Defensive driving doesn't act based on predictions of what external agents _will_ do, which may have regional variation. It identifies what external agents _could_ do, which does not have regional variation, and engages accordingly with rules and physics e.g. by making sure that the vehicle always has a safe escape path if it needs to stop abruptly or swerve to avoid a collision.