Question: is it illegal to pass on a solid yellow line

Answer: No, A yellow line (solid or dashed) indicates that crossing the line will place a driver in a lane where opposing traffic is coming at the driver. A double yellow line is a painted marking separating two lanes of a road. It consists of two parallel, solid yellow lines, and its presence usually indicates a no-passing restriction or no passing zone, where crossing the line is prohibited. Obvious exceptions to this no-passing restriction include emergency maneuvers or temporary traffic flow changes due to road work. Often the double yellow line has sections where one of the lines becomes dashed (in which case it is no longer a ``double yellow''), indicating to the drivers traveling on the side closest to the dashed line that they may pass when it is safe. Double-yellow lines may be used to separate lanes of traffic traveling in opposite directions where passing would be dangerous, or to restrict access to lanes traveling in the same direction, such as HOV and express lanes on a highway.