When Curve-Curve - Reverse Curve is selected as the Transition Type, this option lets you specify the radius for the first and second curves used in the widening.

public PropertyDouble RadiusOfReverseCurve { get; }

Public ReadOnly Property RadiusOfReverseCurve As PropertyDouble
	Get

public:
property PropertyDouble^ RadiusOfReverseCurve {
	PropertyDouble^ get ();
}