What does a solid double yellow line indicate?

A solid double yellow line serves as a crucial visual cue for drivers, indicating that no passing is allowed in either direction. This marking is designed to enhance safety on the road by clearly signaling that overtaking another vehicle is prohibited. In areas where visibility is poor, such as on hills or curves, this line helps prevent accidents by discouraging maneuvers that could lead to dangerous encounters with oncoming traffic.

While passing is legally permissible next to a single yellow line (indicating one direction of traffic can pass, if it is safe to do so), the solid double line unequivocally instructs drivers that such actions are not permitted. Additionally, it does not indicate two-way traffic, as that typically is represented by other markings. Turning is also not permitted from the lane adjacent to a solid double yellow line, as this line focuses on maintaining the integrity of the lane usage and ensuring safety on the road.