What do double white lines indicate?

Double white lines serve as a clear and definitive indication that changing lanes is not permitted. This is often seen in areas where the road design or traffic conditions present increased risks, such as when there are two lanes moving in the same direction with a potential for merging traffic or other complexities that make lane changes hazardous. The presence of double white lines provides a visual cue to drivers that they should remain in their lane and not attempt to switch to another one, thereby enhancing safety for all road users.

The other options imply actions that involve changing lanes or passing, which conflicts directly with the meaning of double white lines. Therefore, when you see these lines, compliance with the vertical message conveyed is crucial for maintaining orderly traffic flow and ensuring the safety of drivers and passengers alike.