A single broken yellow line usually marks the centerline of a two-way roadway where:

A single broken yellow line indicates that passing is permitted in both directions, as long as it is safe to do so. This line signifies that while you can overtake another vehicle, you must ensure that the road is clear and it is safe to pass without endangering yourself or other drivers. The broken nature of the line contrasts with a solid yellow line, which would suggest that passing is prohibited in that direction.

In contrast, the other choices imply restrictions on passing, which do not apply in this context of a single broken yellow line. For example, the statement that no passing is allowed contradicts the meaning of the broken line, while indicating that only trucks could pass or limiting passing to intersections further misrepresents the driving regulations associated with this marking. Understanding these rules helps drivers make safer decisions on the road.