What does a solid white line on the road signify?

A solid white line on the road indicates lane segregation, meaning that drivers should not change lanes. This line serves as a boundary to reinforce the necessity of staying within the designated lanes for safety purposes, especially in situations where lane changes could lead to accidents or create hazards. In essence, the use of a solid white line signifies that the lanes on either side are not intended for vehicular movement across that line, thereby helping maintain order and predictability on the road.

The other options, while relevant to various traffic scenarios, do not correspond to the meaning of a solid white line. For instance, road construction usually includes specific signage and markings to alert drivers, whereas passing regulations and pedestrian crossings are often indicated by other types of road markings, such as broken lines or pedestrian symbols.