What does double yellow lines on a roadway signify?

Double yellow lines on a roadway signify that no passing is allowed in either direction. This marking is intended to enhance safety by indicating that the roadway may not be wide enough for safe passing or that visibility is poor, making overtaking another vehicle hazardous. The double lines serve as a clear visual cue to drivers that they should remain in their lane and not attempt to pass vehicles traveling in the same direction or those coming towards them. This is important for preventing accidents and ensuring a smoother flow of traffic.