What indicates that crossing a double solid white line is prohibited?

When you encounter a double solid white line on the road, it signifies that crossing this line is prohibited. The purpose of double solid white lines is to separate lanes of traffic moving in the same direction where lane changes are not allowed. This regulation helps maintain safe traffic flow and prevent accidents by indicating that the area is not meant for switching lanes.

In contrast, a dashed line would indicate that lane changes are permitted, while a single solid line often permits crossing under certain conditions. A curved line does not provide relevant information regarding lane crossing prohibition. Therefore, the presence of double solid white lines is a clear signal to drivers that they should not attempt to change lanes in that section of the road.