Expand Roundel Geometry and click on the Circulatory Lanes tab.
Circulatory Width is the width of the entire circulatory path measured between the island radius (or the apron radius if smaller) and the inscribed circle radius.
Circulatory Lanes is the number of designated lanes around the central island. There would normally be at least the same number of circulatory lanes as there are lanes on any of the incoming arms.
Lane Width is measured between definition lines and/or lane separator line.
In all cases the Max and Min values represent the limiting values from the adopted design standard and the Default value will be used when the roundabout is first placed. A default value MUST be provided but Max and Min may be blank if there is no limiting value.