What does a solid double yellow line mean?

A solid double yellow line indicates that no passing is allowed in either direction. This marking is used specifically to enhance safety by preventing vehicles from crossing over into oncoming traffic. It often marks the presence of a roadway configuration that may be hazardous for passing, such as curves, hills, or intersections. The intention behind this rule is to help maintain safe driving conditions and reduce the likelihood of head-on collisions. Thus, when drivers see a solid double yellow line, they must remain in their lane and not attempt to overtake other vehicles.