What does a solid white line on the road indicate?

A solid white line on the road indicates that it marks the edge of the roadway. This line serves as a boundary that helps drivers clearly identify the limits of the road, especially in situations where there may be no curb or shoulder present. It is important for maintaining safe driving practices, as it conveys to drivers where they should stay to avoid leaving the roadway, which could lead to accidents. Unlike other lines that might signify a different purpose, such as those indicating where lane changes are allowed or separating lanes of traffic, a solid white line provides a clear demarcation of the road's edges, enhancing visibility and safety for all road users.