In Autodesk Civil 3D 2025, you can define a default roundabout standard, i.e. a standard that will be used every time you place a roundabout unless you actively select an alternative. This can be very useful if you regularly use the same standard.
If you select a standard to use and you do not have a default standard set, the Default Roundabout Standard dialog is displayed. If you select Yes, then this standard will be selected automatically next time you place a roundabout. If you select No, then you will be asked this again the next time you select a standard in similar circumstances.