What does a solid white line on the road indicate?

A solid white line on the road indicates that lane changing is discouraged but not prohibited. This means that while it is technically permissible to change lanes, drivers should exercise caution and consider the conditions of the road and surrounding traffic before doing so. The presence of a solid white line often suggests that the lanes are meant to stay consistent for safety reasons, as this line typically indicates that the adjacent lanes are moving in the same direction.

In contrast, the other options do not accurately reflect the meaning of a solid white line. For instance, a solid white line does not make passing completely prohibited, which would require a different type of line, such as a solid yellow line for opposing traffic. Additionally, a solid white line does not signify the end of a road or indicate a no parking zone; such conditions would be marked by specific signs or different types of lane markings. Thus, the correct interpretation of a solid white line focuses on the emphasis on caution regarding lane changes rather than outright prohibition.