Custom MassDOT Linetypes have been created within the drawing template.

The support files should be copied, in their entirety, to your Civil 3D SUPPORT folder.
They are as follows:
BEAM.shp
BEAM.shx
RETWALL.shp
RETWALL.shx
MassDOT_v2007_r2.shx

MassDOT_Linetypes.lin file has been provided as a courtesy

Any questions, please reply to CAD.STANDARD@state.ma.us