In the Settings dialog, the current style for roundabouts is bolded. When you select an existing style, the buttons on the right side are available.
To modify the style for an existing roundabout, select a roundabout, then click the Modify panelRoundabout Properties drop downRoundabout Styles.
To set the default styles for roundabouts, click the Home tabCreate Design panelIntersections drop downConfigure Roundabout Tools.
Use Set Current to change a non-current style to the current style.
Use Rename to rename an existing style.
Use New to create a new style based upon the default object style. A new style will be created and added to the list.
Use Edit to edit a selected style in the Drawing Style dialog.
Use Duplicate to make a copy of a selected style. An efficient way to create a new style based on an existing style is to duplicate the style, and then edit the duplicate.
Use Delete to remove a style from the list. You cannot delete locked styles or Autodesk styles.