What does a solid white line indicate on the road?

A solid white line on the road serves as a guide for drivers, indicating that the lanes are intended to remain separate and should not be crossed. It helps to maintain safe driving practices by clearly delineating traffic lanes, signaling to drivers that they should stay in their designated lane. Crossing a solid white line could lead to dangerous situations, like collisions or interference with other vehicles' paths, making adherence to this road marking essential for safety on the road.

The other options are not accurate interpretations of a solid white line. For example, while lane boundaries that should not be crossed accurately describes the function of the line, the notion of completely separate lanes pertains more to double solid lines, which indicate more stringent separation. As for prohibiting parking or signaling roadside hazards, these functions are typically indicated by different markings or signs.