What does a solid yellow line indicate?

A solid yellow line primarily indicates that passing is not allowed. This means that if you see a solid yellow line on your side of the roadway, it signals to drivers that they should stay in their lane and not attempt to overtake the vehicle in front of them. This restriction is often put in place in areas where visibility is limited or where it’s determined that passing could be unsafe, such as on hills, curves, or near intersections.

In terms of the context of the other options, a passing zone would be indicated by a broken yellow line, allowing for overtaking when safe. A no parking zone is typically marked with signs or yellow curb markings rather than solid lines. A bike lane is usually indicated by different types of markings or symbols specifically for cyclists, not by solid yellow lines. Therefore, the correct answer reflects the safety measure and legal restriction represented by a solid yellow line on the roadway.