What does a solid white line on the road indicate?

A solid white line on the road serves to indicate that it is used to separate lanes of traffic that are moving in the same direction. This marking is important for maintaining a safe flow of traffic and offers guidance to drivers about where they can and cannot change lanes. When a solid white line is present, it typically means that changing lanes is discouraged or prohibited, as it helps to prevent accidents and maintain order on the road. This is crucial for ensuring that all drivers remain aware of their positioning and the limitations on their movements within a lane, contributing to overall traffic safety.