On a two-lane road, what does a solid white line mean?

A solid white line on a two-lane road indicates that changing lanes is not allowed. This traffic regulation is in place to enhance safety by preventing vehicles from switching lanes in areas where it may be dangerous, such as near intersections or in heavy traffic. The solid white line serves as a visual marker that signals to drivers that they should remain in their lane and not attempt to cross over.

In contrast, the other choices refer to different conditions or regulations that do not apply to a solid white line. For instance, a broken white line would indicate that lane changes are permitted, whereas a solid white line specifically prohibits that action.