What does a solid white line signify?

A solid white line signifies that it separates lanes of traffic moving in the same direction. This line is used to indicate that changing lanes is discouraged but not illegal. It serves as a guideline for drivers, emphasizing the importance of maintaining lane discipline for safety and smooth-flowing traffic.

In contrast, the other options are not appropriate interpretations of a solid white line. While a no-parking zone might be indicated by different signage or markings, it does not directly relate to the meaning of a solid white line. Similarly, the option regarding changing lanes is misleading since a solid white line specifically indicates that lane changes should be avoided where possible. Lastly, U-turns are governed by specific signage and road conditions rather than the presence of a solid white line. Thus, recognizing the role of a solid white line is crucial for safe driving practices.