Import Civil 3D Object Layers
Ron Couillard of USCAD demonstrates a method of how to import Civil 3D Object Layer Settings from one Civil 3D drawing to another via an undocumented feature.
From the USCADBuilding YouTube channel
and Ron Couilard's blog on USCAD.com
This undocumented feature has existed in Civil 3D for a few releases. Don't count on it working tomorrow.
If you don't have Civil 3D 2017 or 2018, you probably want a separate Object Settings drawing and use the ACAD INSERT command with the EXPLODE checkbox checked.
The 2017+ Reference Template Tools can be employed to pull only Object Settings from one drawing or template to another.
See the Who Broke Civil 3D Reference Templates blog post with videos and details about the issues.