A centerline is the painted line marking the middle of a roadway, separating traffic travelling in opposite directions. Centerlines are typically yellow in North America (white lines separate lanes travelling the same direction). Solid centerlines indicate no passing, while broken lines permit passing when safe. Double solid lines prohibit passing from both directions. Centerline painting and maintenance is a routine public works function, ensuring road markings remain visible for traffic safety. Road marking standards are set by provincial transportation departments. The condition of centerlines and other pavement markings affects road safety, particularly in poor visibility conditions.