What do double double yellow lines signify on the road?

Double double yellow lines are a significant traffic control measure indicating that crossing these lines is prohibited. They represent a physical barrier that separates lanes of traffic moving in opposite directions, emphasizing that drivers must not attempt to pass or cross over these lines at any point. This marking is typically used in areas where it is particularly dangerous to change lanes or where visibility is limited, enhancing safety on the roadway.

In contrast, the other options suggest possible actions that can be taken on the road. For example, merging lanes or passing would not be safe where double double yellow lines are present, as these lines clearly communicate that such maneuvers are not allowed. Additionally, the indication of a bike lane would not be reflected in this type of marking. Thus, choosing the option that states these lines signify a barrier and prohibit driving underscores the important safety role they play in traffic regulation.