When is it permitted to change lanes with a broken white line?

Changing lanes with a broken white line is permitted when it can be done with caution. This type of line indicates that you can switch lanes legally if it's safe to do so, allowing for lane changes to merge into traffic or to pass slower vehicles. Drivers should always ensure they check their mirrors and blind spots before making such a maneuver to guarantee it is safe to proceed.

In contrast to the other options, emergencies are not the only circumstance permitting a lane change, as this could lead to unsafe conditions if not done carefully. Traffic signals indicate specific actions at intersections, rather than lane change legality. The statement that it is never permissible to change lanes with a broken white line is incorrect, as this line design is specifically used to show that lane changes are allowed under proper circumstances.