What does a solid double yellow line indicate?

A solid double yellow line on the roadway indicates that no passing is allowed in either direction. This marking is used to help ensure the safety of drivers by clearly conveying that it is unsafe to cross over into the oncoming traffic lane for the purpose of passing another vehicle. The presence of a solid double yellow line means that there are potential hazards ahead, such as curves or intersections, where visibility is limited, making passing dangerous. This rule is critical for maintaining safe driving conditions, as it helps prevent collisions that could occur when vehicles attempt to overtake on a road where passing is prohibited.