Offset Mode
Note
This is the Offset tile in the Edit palette of the Meta Road editor mode (see The Meta Road Editor Mode).

Offset Mode sets the center-line offset relative to the Road Reference Line — this is the Lane Offset of the road model. You edit the offset curve just like a spline: set any shape, add/delete nodes, and edit tangents.

Selection
In the Details panel, the Selection group edits the selected Offset Key:

See also
Lane Offset — the road-model concept this mode edits.
Road Reference Line — what the offset is measured from.
Width Mode — the other curve-editor sub-mode, for per-lane width.