On one-way roads, what color lines are typically used for the left-edge?

On one-way roads, yellow lines are used for the left edge to indicate the separation of traffic traveling in the same direction. This is important for guiding drivers and providing clear visual cues about roadway boundaries. Yellow lines are traditionally used to delineate lanes and to help drivers stay within their designated path without veering off into oncoming or opposing traffic, which is especially critical in one-way environments.

In comparison, white lines are used for the right edge of one-way roads, helping to distinguish the boundary of the roadway. Red and blue lines are not standard for marking edges on roadways, as they typically indicate other traffic situations or conditions. Thus, the use of yellow lines on the left edge of one-way roads is consistent with standard traffic control practices and helps enhance safety on these types of roadways.