To Add an Approach

1. As with creating a new roundabout, to add an approach to a roundabout you need to be able to pick the alignment. Draw a polyline to represent the centerline of the road if one does not already exist.
2. Select the roundabout, then click the Modify panelAdd Approach.
3. Select the approach centerline roughly at the point at which you anticipate it will join to the existing road. The New Arm dialog is displayed.
4. Enter a Name, Description and/or Notes if you wish.
   Tip: If you are running in Civil 3D, we strongly recommend that you name the arm now so that the alignments are created with the correct names. AutoCAD Civil 3D 2018 does not rename alignments if you change the roundabout arm names after creation.
5. Add information about the Approach road.
   • The Central Gap Width is the distance between the offside definition lines of the approaching lanes and the departing lanes.
   • Set the Approaching and Departing Lanes and Lane Widths.
6. Click OK. The Arm is displayed.
7. If the arm does not display, then you may have picked the alignment too close to the roundabout. Try again. If you still can’t add the arm continue to the next one and add the arm after you have adjusted the alignment.