What does a double solid white line mark on the road?

A double solid white line on the road indicates that travel in the same direction is permitted, but crossing these lines is prohibited. This marking is designed to maintain safety by discouraging lane changes when it would be unsafe to do so, often in areas where visibility is limited or where merging could lead to accidents. Drivers are expected to remain in their lane and not cross the double solid white line under any circumstances, ensuring smooth traffic flow and minimizing potential hazards.

Other options reflect misunderstandings: travel in both directions is not permitted across a double solid white line, nor is passing allowed. The presence of solid lines—regardless of whether they are single or double—indicates restrictions on lane changing and passing, reinforcing safe driving practices.