What does a broken yellow line signify on a two-way road?

A broken yellow line on a two-way road signifies that passing is allowed, but only if it is safe to do so. This means that drivers can cross the broken yellow line to overtake a slower vehicle, provided that there is no oncoming traffic and they can safely return to their original lane. The broken line serves as a guideline, indicating that while passing is permissible, caution is necessary to ensure the safety of all road users.

The other options describe concepts that do not apply to the meaning of a broken yellow line. For example, prohibiting lane changes or indicating a no-passing zone does not align with the purpose of the broken yellow line, which is intended to promote safety while allowing passing under the right conditions. Additionally, a lane for slower vehicles would typically be marked differently and does not refer specifically to the use of broken yellow lines on a two-way road.