What type of lines mark the center of the road and separate traffic flowing in opposite directions?

Double solid yellow lines are used to mark the center of the road and indicate that passing is not allowed for vehicles traveling in either direction. This type of line helps ensure safety by clearly demarcating lanes that are meant for opposing traffic. The solid lines signify that crossing them is prohibited due to potentially hazardous conditions.

In contrast, broken yellow lines indicate that passing is allowed when it is safe to do so. Double solid red lines do not typically fall within the context of road markings for separating traffic in this manner and are generally used for different traffic control purposes. Broken white lines indicate lanes of traffic moving in the same direction and are not applicable for separating opposing flows. Thus, the use of double solid yellow lines is specifically designed to prevent unsafe maneuvers in areas where different directions of traffic are present.