A dashed yellow line next to a solid yellow line indicates that passing is permitted on the side of the dashed line but not on the side of the solid line. This setup is used to safely regulate passing maneuvers, allowing vehicles traveling in one direction (the side with the dashed line) to overtake when it's safe, while preventing vehicles on the other side from doing so. This control helps manage safe passing on roads where visibility or road conditions might vary between directions, maintaining safe and orderly traffic flow.